Re: Supernatural
I believe patch 1.38 provided the ability to turn supernaturals off. If you go into the game options and click on the population tab, you can un-tick Vampires, Werewolves, Fairies etc.
Zombies can only be disabled by avoiding the full moon - turn the moon option to one phase only (not the full moon!).
These options will not get rid of supernaturals that already exist in a hood, it will just stop more from coming. If you have existing ones in a hood that you want to get rid of you will need to use a cheat - turn on the testing cheats by pressing Shift+Ctrl+C then type in testingcheatsenabled true
Then shift click on the mailbox and select the Supernatural Population Control. You can get rid of any existing ones from the choices there.
To turn the cheat back off afterwards, use Shift+Ctrl+C and type in testingcheatsenabled false