fascinating idea. Simple, pure, great idea for an RP.
I feel like it would be better as an open, sandbox, style game, giving everyone in the building the full range of human emotions at their disposal.
master devices: like a haunted building, or a curse on the land is a good idea, because it gives everyone a fall back subject when their character's world slows down. A common theme in every character would even work (like if everyone was an addict of some kind, or if everyone in the building was coincidentally from the same general nationality) I'll show you all of my brainstorming on this subject:
I - the haunting
II- landlord is a murderer
III- IRS is trying to demolish the building (kind of a rent thing i suppose - but no one would be squatting, so its legitimately different)
IV- everyone in the building was witness to a front-page headline murder case. This causing detectives and accessories to the murder to constantly drop by for malevolent or beneficial visits. I suppose the murder would have happened in the pool, or the front entrance, maybe on the street in front of the building
V- lots of snow, no one wants to go outside (this has actually happened to me two winters ago, it was really fun. lots of blankets and sexy encounters for "warmth" This might cause a Christmas or Thanksgiving theme, though, kind of lame if not done well)
I- everyone's a musician/artist/dancer/something creative
II- everyone is of the same race (not relevant in story, but in everyone's inner-monologue)
III- all alcoholics, or cocaine addicts, or cigarette smokers, or pot-heads, or all different varieties of addiction. This is supposed to be inspirational, not dark and depressing. Like, they're all living good lives, despite their addictions.
IV- all students at college-grad school-or higher (18-35 year old characters, always studying)
V- everyone is really spiritual and a little bit crazy in to it (it would make the game eerie)
This is all just to get ideas rolling. I'm not sure what everyone wants from this RP, but I think I'm going to be interested no matter how it turns out.