Maybe Quigley really did die in the fire:

[doetwin]

This is a theory I've had for some time and I should first point out that this is solely based on the books and has nothing to do with the Netflix show. When the mysterious snow scout revealed himself to the Violet and Klaus, the evidence that he was Quigley Quagmire may have seemed overwhelming. After all, he was described as looking "so much like Duncan and Isadora that he could only be the Quagmire triplet." But we also know that there were two other people who looked "so much like Duncan and Isadora", those two people, of course, being Duncan and Isadora themselves. The snow scout was obviously a male, which still leaves open the possibility that he was Duncan just pretending to Quigley. And honestly, I think this was the case. There is just so much about the story he told the Baudelaires that doesn't make sense.

A common head-scratcher that's been pointed out by fans, including myself, is the snow scout's statement that the reptile room was empty when he reached it, meaning that the events of TRR had already happened. However, in TAA, Isadora stated that she and Duncan had lived at Prufrock Prep for at-least 18 months, which is definitely longer than the time period between Monty's death and the Bauderlaires' arrival at the boarding school. I know he showed the Baudelaires Monty's book about the Mortmain Mountains, but let us not forget that he spent a lot of time in the company of Bruce, who had also been to Monty's house. If Bruce picked up that book and took it to the mountains with him, the scout could've easily snuck it from him. The scout also claimed that he knew Count Olaf had disguised himself as a lab assistant there simply because of his suitcase. But let's not forget that Violet removed all the incriminating items from that suitcase in order to show to Mr. Poe, and there was never any mention of those things going back inside the suitcase. However, if the scout was Duncan, then he would've already heard stories directly from the Baudelaires about all the disguises Count Olaf had used.

Despite the fact that Violet and Klaus hid their faces when they entered the cave, the snow scout in the sweater still knew that they were the Baudelaires, as this was how he addressed them when he woke them up to take them to the headquarters. The only way he could've recognized them was by their voices, yet at no point in the snow scout's story did he mention having heard the Baudelaires speak, either in person or through a recording. He did claim to have seen a picture of them, but like I already said, this wouldn't have helped him recognize them in the cave. Duncan, however, definitely had heard the Baudelaires speak before, which means that he would have been able to recognize Violet and Klaus solely by their voices.

The scout claimed to have gone from Monty's house to Paltryville completely on foot. This means that he walked along lousy lane, a lane which is already extremely unpleasant to DRIVE along. Even if the snow scout had enough pluck and determination to make that sort of journey, the horse-radish smell should've made enough of an impression on him to at-least mention it the Baudelaires when telling them his story. Once again, he claimed to known all about Count Olaf having in Paltryville just by his fake nameplate. 

There are a lot more holes in the snow scout's story, but this thread is already really long. I guess the real question is why Duncan would have impersonated his deceased brother. Seeing as neither the Baudelaires nor the Quagmires were too keen on spending the rest of their lives up in the air. I think it would've only been natural for the Quagmires to want to dismount the SSHAMH as soon as possible. One way to achieve this would've been to steer the device to an area in the Mortmain Mountains that was level with the balloon's current height, so that Duncan and Isadora could've gotten off safely. This is, I think, what they were planning to do.

So this begs the question of why Isadora didn't come with Duncan. The answer is that there was a good chance that Duncan, Isadora, and Hector reached the MM as the sinister duo were burning down the VFD headquarters. The sight of such a terrible fire could've easily stirred controversy among the triplets. If Isadora changed her mind about wanting to return to solid earth, it was probably because she wanted to be somewhere where fire, the reason she had lost her parents and brother, couldn't reach her, even if it wasn't her ideal lifestyle. If Duncan was willing to risk these dangers anyways, it could've easily led to a bitter and sorrowful parting between the two surviving triplets, with Duncan wandering the mountains and Isadora remaining in the air with Hector.  Upon running into Violet and Klaus, Duncan probably would've been afraid that they would disapprove of him walking out on his sister, which is why he would've lied to both the Baudelaires and Kit Snicket, and told them he was Quigley.

Ultimately, Duncan loved his sister more than anything, which is he would've immediately agreed to go to her aid in a helicopter upon hearing she was in danger. I know Kit seemed to confirm that all 3 Quagmires were present when she told the Baudelaires about the Great Unknown, but chances are that she only saw a Quagmire boy capturing the eagles above and simply assumed that there was another Quagmire boy with Isadora and Hector on the SSHAMH, without actually being able to see anyone on the balloon. Once the SSHAMH crashed, everything was so chaotic and Kit had to make her raft and escape so quickly, she probably didn't have time to notice that there was only Quagmire boy.

[Optimism is my Phil-osophy]

Oh... It makes a lot of sense. For a long time I have been trying to show that Kit had vision problems (there is a picture showing her wearing glasses, there is a clear indication in TE that protecting the glasses is essential so as not to lose them in a storm at sea, and there is the fact that everyone else saw an entity in the form of a question mark and were confident in going to that, while she wasn't sure what it was and decided to run away, even though she realized that the entity emerged from the water).

So, I think it makes sense that she got confused in what she saw involving triplets.

However, something about Quagmire's behavior still bothers me. He, while wearing a mask, tried to pass the secret VFD code to the Baudelaires: "I didn't realize it was a sad occasion". What would you have to say about this behavior? After he revealed his face, he started to pretend he was not a member of VFD. In addition, Kit seems to have had a partnership with that Quagmire. How did this happen, if he and Ducan are the same person? (I'm not disagreeing, at least not yet. I just want to understand your point of view in this situation).

[carmelita0cheryl]

Cool theory

Just guessing, Olaf could have had a small nametag somewhere on the suitcase perhaps. "That's Uncle Monty's house! He was our guardian until Count Olaf arrived, disguised as – " "As a lab assistant," Quigley finished. "I know. His suitcase was still there." (Slippery Slope chapter 8)
Otherwise idk how the scout would know the suitcase was his or it would, as you think, be Duncan because this is highly suspicious.

The next part is also very suspicious. As Quigley could have read the Daily Punctilio and knew they were boy, girl and a toddler girl, as they were two in the cave - girl and boy about the same age he could've tried his luck. That could be why he repeated the word 'Volunteer Feline Detectives' to find out if it'S them.
Or it could have been Duncan who got off the Hot Air Mobilhome to help the Baudelaires and repeated the word to be sure Violet and Klaus understood.

The scout didn't mention the Lousy Lane itself, as he is a cartographer he could take a straightforward path to be there earlier, but propably wouldn'T get away from the smell anyway...


Also do you think Quigley made maps before the fire?

"Quigley Quagmire?" Fiona asked. "The cartographer?"
"He's a friend of ours," Klaus said. "Do you know him?"
"Only by reputation," Fiona said, using a phrase which here means "I
don't know him personally but I've heard of the work he does."
"The volunteers lost track of him a long time ago, along with Hector
and the other Quagmire triplets." (Grim Grotto Chapter 4)

But I must say this theory is well investigated, makes me think about it a lot!

[Optimism is my Phil-osophy]

Well, that explains that the survivor would not be Quigley ... That sentence on page 13 would never make sense in the Quagmire fire. Experts knew that there were at least two survivors of the Quagmire fire, Ducan and Isadora. It would make no sense to say that experts now suspect there may be a survivor of the fire, but its whereabouts are unknown.

Was Ducan trying to hide that Beatrice had survived the fire?

[doetwin]

Thank you for all of your responses so far. I feel like now would be a good time to address the rest of the things that don't make sense about the snow scout's story. Monty's house was in Tedia, which means the Quagmire home would've had to have been in Tedia, or just outside it, in order for there to have been a passage connecting it to Monty's house. In TAA, It was never made clear exactly what personal information the Baudelaires and the surviving Quagmires exchanged with each other. However, it is made clear that the Baudelaires told the Quagmires where they had grown up, as Duncan was about to show them an article about something that had happened there.

"And then in the Verona Daily News," Duncan said, "there was a man who had thrown a
rich widow off of a cliff. He had a tattoo of an eye on his ankle, but he had eluded authorities.
And then we found a newspaper from your hometown that said-"

Since the Baudelaires told Duncan and Isadora where their hometown was, it's safe to assume that Duncan and Isadora told the Baudelaires where their hometown was. If the Quagmires had mentioned anything about Tedia, Violet, at least, would have recognized it like she did when she heard the name later in TVV.

"The next village on the list is Tedia," Klaus said. "That name is familiar to me."

"That's near where Uncle Monty lived," Violet said. "Let's not live there – it'll make us miss Uncle Monty even more than we already do."

Yet none of the Baudelaires ever remarked, verbally or inwardly, about whatever city the Quagmires grew up in.

[Optimism is my Phil-osophy]

Well ... The time they spent at Prufrock Prep was half a semester, according to Lemony's letter to the dear editor, printed in TMM. This is more than enough time for the Baudelaires and Quagmires to become close friends and to know everything about each other's lives ... At least the most important things. After all, they became close friends. Now, how far away the VFD tunnels can be ... I can only rely on prior information ... The City tunnels are in fact restricted to the city itself. From what you're saying, the Quagmire hometown must be Tedia. But I still don't understand where that conclusion takes us.

[Hermes]

Well, there's lots one can say about this. Possibly the most important question is whether the Baudelaires would have recognised Duncan. Are you assuming he and Q were identical? But we aren't told that, only that they were very similar (though we are told, absurdly, that Duncan and Isadora looked absolutely identical). And in any case, you can tell identical twins apart if you know them well, as the B's certainly did with the Quagmires. (Also, it puts Duncan in rather a bad light if he is pretending to be his brother while capturing the affections of his not-quite-girlfriend from TAA.)

The chronological problem is very real, but it exists in any case; Duncan would surely have known that Monty's death happened long after the fire, so it's not clear why he would come up with this clearly inconsistent story.

I don't think there is any real answer to these puzzles, except that DH changed his mind. (At one time there was quite an influential theory that Q was indeed lying about what happened, and that he was in fact the survivor whom Gustav Sebald was referring to, hiding in a snowman. But if that is so, it does not seem to go anywhere.)

But as for how he knew about Olaf being at Monty's house - perhaps he had read TRR? And his knowing about Shirley may imply that TMM had also been published at this point. He may not want to shock the Baudelares by telling them someone was writing books about them. (*Is shot by Jean Lucio*.)

[Optimism is my Phil-osophy]

Well ... I think I will always need to repeat about when the books were published in Lemony's universe ... (which was at least after a few years of the main events have passed.) But I have to admit that Ducan needs to look different of Quigley ... After all they are triplets formed by fertilization of separate eggs, and we can be sure of that by the existence of a person of a different gender ... Although it is possible, but very rare, that triplets are a combination of a identical double and a twin of a separately fertilized egg. But this is a very rare event. They are the plurivitelino triplets. The photograph from LSTUA chapter 4 (which probably refers to triplets (but I don't think they are the Quagmire triplets)) are not identical triplets. 

To sum up my last paragraph ... it is possible that they were identical, as shown on the Netflix show ... But it was unlikely. But, we are talking about a fictional universe ... An asoue universe ... So ... Even though it is unlikely it is really a real possibility, I would say.

About Quigley being omitting things ... I can say that this is a fact. He is a member of VFD. He even uses the code to find out if the Baudelaires are members of VFD, and when they don't respond properly, he adopts another strategy. Quigley acts like Hector. He denies being from VFD, and gives incomplete information. And he resorts to lies. He was trained for this. 

Kit does that too. It gives incomplete information about triplets D. Captain W, also gives incomplete information and resorts to lies, especially about the telegraph, which was not broken. Incredible as it may seem, the only VFD person who apparently isn't telling intentional lies is Lemony Snicket himself.

However, what for me is evidence of Quigley's survival, is the fact that Lemony states that (during the TSS publication period, which was years after the main events described in TSS), Lemony implies that a young cartographer (one of the best of his generation) is still alive. As Fiona later claims, Quigley has a reputation in VFD. So, it is easy to conclude that the cartographer is Quigley and that he actually survived.