AnnaKarenina, it was pretty obvious that Jerome didn't receive that letter, and that the doorman took it. The hook-handed man could have been posing as the doorman for ages - he isn't seen in TWW, TMM, or TAA.
This is all clear in Jerome's letter to Jacques.
Also: The room above the penthouse was probably some kind of V.F.D. refuge in case of trouble. In TSS, Quigley said that the tunnels were built by volunteers to lead to safe places.
It's also worth mentioning that the Snicket File page 13 picture was taken in front of 667 Dark Avenue.
That bit of evidence has been discussed someplace in Sardonic Series. No one is quite sure how Beatrice can be partially the Baudelaire mother, but there's a theory that she was the children's nanny. If DH is reading all this, he's probably laughing.