I play with as few occults as possible. I do have the Supernaturals pack installed but I want to keep them confined to their original worlds. So as @texansky said I have them all unchecked on that last tab in the Options menu. This means I don’t see fairies elsewhere, and I don’t find that other sims have suddenly turned into vampires, etc.
I do still get zombies when it’s full moon. The only way I know to remove them is to have testingcheats enabled, then right-click (I think?) on the mailbox and you get an option about controlling supernaturals (among other things like changing season etc.). That takes you to a menu where you can remove the supernaturals you want gone. You have do it each time, e.g. a zombie will turn up at my house, but I click on the mailbox and then they quickly become like a normal sim, get in a taxi and go away.
I do also have ghosts, but they don’t bother me. You might be able to remove them in the same way but I can’t remember, as I’m usually just focused on getting rid of those creepy zombies!