3. DRACULA - MADS MIKKELSEN
Is this one too obvious? I don't care. He's amazing. The Danish actor is, very sadly, done playing Hannibal Lecter on television, and now he can bring that old world charm to a similar role. He's been a Bond villain in Casino Royale, he's set to appear as a villain in an upcoming Star Wars film, and let's just make him Dracula to boot. He is this sort of amalgamation of Christopher Lee, Bela Lugosi, and Donald Pleasance... but sexier!
In terms of the team-up, it's obvious that Dracula should be the charming rogue of the group, kind of a Tony Stark by way of Prince Zuko from "Avatar: The Last Airbender." This actor would crush that role in his sleep. Imagine him chuckling to himself upon meeting Frankenstein's monster, or going full-Lando on the lady Mummy with the hand kiss and the velvety voice.