New Roster Update: Version 5.1
Additions: Issac, Medusa
Removals: Sheriff, Matthew
New! Medusa - Let me start by addressing the elephant in the room. I have Medusa because I think she is pretty likely, I know 3 KI reps seems a little unexpected, but I wouldn't be surprised if we got a dark semi-clone of the Goddess of light. She's basically my prediction for a semi-clone and I couldn't really think of anyone else to add. Sakurai is really promoting Kid Icarus in the trailers and footage so I don't see Medusa to be impossible. However I wouldn't be surprised if all we got was Palutena.
New! Issac - Issac has established a bigger world than Matthew has and due to Alph and Spirit Tracks Link not being in the game, I decided to go with Issac for once.
Starfy - Starfy is one of the most likely, he's had 3 GBA installments, a 4th on DS, and a fifth western release on DS. He has become a pretty big Nintendo All-Star and has a lot of Move Set Potential. I suggest others add him.
Mewtwo - Mewtwo will return. There is no question about it. What will be of his upgraded awakened form though? My guess is that you earn this through battle or Final Smash and maybe lose it when KO'd. Footage of the movie: "
Extreme Speed Genesect: Mewtwo's Awakening" that this new form is in fact more powerful and faster. He only changes back to Mewtwo when he is weakened or done fighting. So it makes sense to be a form that you earn, but don't keep forever as it's powers are limited.
Genesect - My newest addition. I didn't add Genesect because he's a new Pokemon, I added him because we need a Pokemon that hasn't already been playable. Genesect fits the description Sakurai gave on how he adds Pokemon characters. Genesect being in SSB seems very likely and has so much potential. He has become greatly popular in Japan as well.
Paper Mario - Bowser Jr is very likely to be the 5th Mario rep, but I see Paper Mario to be more preferred and unique. It just seems like the more logical choice.
(See the move set I made at the bottom of this post.)
Bomberman - Konami has recently acquired one of the most popular/iconic third-party characters from the deceased Hudson Soft. Bomberman has had as much affiliation with Nintendo as any of the third-parties if not more and has had games on practically every game machine since NES. It hasn't been confirmed that third-parties like Snake will return and Sakurai and Konami may want to make use of this character especially since we can expect a new age of Bomberman due to his recent buyout of a major gaming company.
Snake - Most games that have guest characters usually only have them once. If any game does that it should be Smash Bros. I'm sure Sakurai may want to prioritize Nintendo Characters in a Nintendo fighting game, and not have too many Third-Parties. We could have Sonic, Snake, and Mega Man, and though it's hard to imagine SSB without Sonic, there is the possibility either 3 will be too many and Sakurai may want a second third-party to have a chance. I just don't see third-parties as veterans, but Sonic seems too popular to leave. (I know Snake was added as a favor, but it was a request for him to make an appearance, not be a veteran for life. That'd be a pretty huge favor)
Jigglypuff - I personally don't want Jigglypuff to go and could suffice with Mewtwo over Lucario (even though I like Lucario better) but Jigglypuff hasn't really made any special appearances in anime or game. She could be more unique than Lucario with her fairy moves, but people suggest I keep Lucario. I think veteran status being her biggest reason for staying will not carry on this time, especially since she is a Pokemon and Pokemon risks an all veteran roster.
Mii - I think it's obvious he will use moves from Wii Sports, Wii Party, StreetPass Quest, and maybe even Pilot Wings Resort.
Costumes:
Villagette - I predict half of Villagers colors will be Boy, and the other half will be girl.
Dry Bowser - Either 1 costume or a second set like Wario & Villager.
If you have opinions or constructive Criticism, please give suggestions below. Tell me if you think I should go back to my old roster.
(Credit to Ariand/AEM for making the Icons of Palutena, Little Mac,and Mii)
Bonus!: Starter Roster (My predictions of characters you will have at the beginning of the game.)