OK this isn't a betting game but here's my conception of the odds and a couple of thoughts.
Ray Haffner: 15% chance - overall a strong fit but not a knockout in terms of being an exciting ending because he's just not that great of a villain. Likes Lisbon so he will be be punished. (This is basic TV psychology)
Walter Mashburn: 15% chance - Good villain and remember, he had sex with Lisbon so he's got a big payback coming. Maybe in "He is Mar" the "r" is an incomplete "s". His odds would be a higher if he were on the list of 7 and if we'd seen him in episodes more recently.
Multiple people: 15% - "He is Mar" could be an incomplete "He is Many". Kind of a cop-out but fits what has been going on. This would maybe leave room for the storyline to continue in the future. If this is the case, then Stiles is heavily involved.
McAllister: 10% chance - Smart guy, cagey, and seems pretty creepy in a restrained way. Plus there's extra points for being with the show from the start, because the writers would want to have a go-to guy in case they need to wrap the story up.
Brett Partridge: 10% chance - It would be pretty bogus to pull a zombie trick but as PJ says, anything can happen on TV. Plus he gets points for lurking since the beginning.
Kirkland: 10% - Evil as they come but not a cult leader and incapable of seducing LM. He sure looks like he had a face transplant though.
CBI Ron: 10% chance - A somewhat hokey choice. He'll need some character development real quick to be viable. But potentially an appealing lurker character.
Reede Smith: 5% chance - Likes cold weather because he's fat. This clue fits but many of the others don't, and he really doesn't have much prominence or character development yet.
Bertram and others: 10% combined. Bertram can't win at poker, and he doesn't seem like that strong of a villain.
