A couple more ways to deal with zombies and unfinished room moodlets:
1) NRaas Mods
Use the NRaas Master Controller to change the occult type of a zombie to a conflicting type such as werewolf, then use the mod to remove the werewolf to make the sim a normal human. You can find this setting under the Intermediate settings.
2) Planters
Planters allow you to grow your small plants indoors, you cannot grow trees inside them. You'll have to ensure there's a 1 square space around each planter to avoid pathing problems when tending plants in them.
3) Grass Rugs
Having the expansion Into the Future really helps here as you can buy a grass rug that allows you to grow plants indoors or on top of roofs without needing to use moveobjects cheat! Now you can create indoor gardens and greenhouses without the unfinished room moodlets. Unlike planters you can also grow trees on these rugs, and you can do landscaping on them too such as creating indoor ponds.