If a zombie bites a vampire does anything happen? If it does, who gets what? I mean, they're both already dead/undead...

What about a zombie biting a werewolf?

A werewolf biting a zombie? Who turns into what?

Does it take a silver bullet to the brain to kill the zombie, then?

If a vampire bites a zombie, will it die if ya shoot it in the head, or do ya gotta drive a stake through it's heart, too?

Yes, they both become Grateful, yes, yes, and moves from 1st to 2nd base, yes (call the Lone Ranger), the latter (call Tonto too).

Ah man!!