The Legend of Zelda:
Monkey's roster is generally good, although I am doubtful of Tetra, especially without Toon Zelda. Swampasaur gets a slight edge for sticking with the ones we have.
Fire Emblem:
Swampasaur wins again. The problem I have with Monkey's roster is that it replaces Ike with Chrom. Chrom's inclusion itself is plausible, but I don't think he will end up replacing Ike; rather I see both of them together. Swampasaur has what I consider the most likely scenario; Marth, Ike and Roy.
Misc.:
I'm thinking we're only going to get one of Isaac or Shulk, not both, so I think both rosters should trim one of them off. Swampasaur wins again, however, because he features Mii's, which should be treated as confirmed due to the leak containing Villager, Wii Fit Trainer, Mega Man, Little Mac, Mii and Pac-Man. A roster is impossible if there is no sign of even one of Little Mac, Mii or Pac-Man in the roster.
Third-Parties:
This is the hard one:
Swampasaur's roster has three third-parties; which is a good amount. However, the roster does not have Pac-Man, who is confirmed due to the leak. If the roster had Pac-Man in place of Snake, this would be the most realistic third-party scenario.
Money has four third-party character, which is excessive but not totally impossible. It cuts Snake, who is honestly the only likely cut to be made. It also has Pac-Man, which is a plus. However, Rayman's inclusion is a big no-no since there just isn't enough going for him to be a remotely possible contender.
So I give this to Swampasaur.