I'll talk about the game setup because I kinda want people's input on that because my theories rely in some part on what I think we're up against.
First of all, at this point, there's no doubt in my mind that Lock and Oogie Boogie are present in this game and are anti-town. Until we talked about a possible SK, the setup I had in mind was Lock, Shock and Barrel are Mafia Goons with Oogie Boogie as Godfather (or powered Mafia).
4 scum to 11 town seems about right (just under the usual 3:1 ratio).
Now, comes talk of an SK. I don't want to dismiss it but it troubles me because in the movie L,S,B are Oogie Boogie's henchman so them being on the same team makes a whole lot of sense. I can't see OB being a lone SK, the one character I can see as a third party role is Santa Claus (or Sandy Claws like us Halloween Townfolk like to call him), he's the only character that is not from Halloween Town but then again making Santa Claus a serial killer is pretty twisted.
Any comments?