My area of expertise! I play vampires very very often in Sims 2. If they live on the apartment lots, they can die from the sunlight if they venture outside into the commons. They sometimes walk home from work or somewhere else, and if it was during the daytime, that can be bad too.
Vampires generally need to stay inside to avoid the sunlight, but if they live on the apartment lots as "townies", they are beyond your control to be sent back inside. Or if you play several custom families, the others are treated as "townies" until you switch to another family on the same lot to play. This might not be good.
However, if you're concerned about them wandering around during the daytime while you're playing a different family on the apartment lot, you can grab Carrigon's
Daytime Vampire Hack. She stated in one post related to this mod that it worked with AL/MG. There's two versions, one with OFB and one without OFB. That might be your cup of tea to keep the vampires from dying on the apartment lot.
You can also look into Pescado's
Apartment Hack where it moves the "Rent Hour" from around 12 PM (noon) to around 8 PM when it gets dark so the vampires can go out to the mailbox to send their rent money in. It also prevents the Sims from coming outside to stand for hours and do nothing.
If you plan to put vampires into their own apartment lots, make sure they have coffins to go to sleep in.
Anything else you need to know about?
