That would indeed be interesting. One thing about the Innistrad vampires is that they need an adult human's worth of blood every month, at any point between full moons, to survive, so they more or less have to murder people. They can't- or, at least, don't- just sip a little blood from a different person every night and call it good enough (even though that would probably be more efficient).136 if one group of "wolves" need to also win from the other 2 you could make it so the Vampires have only x nights after there are no humans before they also need to kill them self(as they need blood). If you can somehow balance the other 3 teams around that you may end up with a situation where the Vampires need to protect the last human if they want to win, which would be interesting.
142 You should write up a rolesheet. It might be interesting...