I think the "scare/haunt" need could be named something like "attention" meaning both good and bad ghosts have a need to be noticed. It could drain much faster for bad ghosts cause they want to scare people and make mess. Good ghosts would rather help people without being noticed, like guardian angels but sometimes they feel lonely or want their loved ones to see that someone watches over them.
It would be cool if type of death gave ghost unique power like sims that died in fire and become good ghosts can extinguish fire and bad ghosts can set fire (never played as ghosts so not sure if that thing is already there but if there is it could get somehow improved).
As for cemeteries they should be in a patch but funerals might be GP-exclusive. Or maybe in patch too but only as "party" with no coffin and stuff but some limited interactions, but GP could expand the event adding coffins and even more interactions.