Unplayed Sims in other households won't have much story progression in vanilla game, except for skills and friends they make when they are out and about in an active neighborhood where your played Sims sees them. MC Command Center Mod gets unplayed Sims married, moves them, has them have offspring, and some other autonomous mature stuff with another module.
No, we can't have NPC housemates, there is no cheat. The only way to do it is to add them, then not play them. :)
The service Sims have hidden traits, that can be input in the cheat window. Something like, is_nanny, etc, but I know it's not quite that simple. There's a thread about all the hidden, non reward traits, somewhere around here. I'll hunt it up.
Hmm, I can't find it. @LeGardePourpre, did you once have a thread that listed all the hidden trait cheat inputs? I seem to remember one, but I could be dreaming. :p
