Alright, I'll drink the Kool-aid and join the camp that thinks this "leak" is real. Why do I say that? Because I never believed for a second that Mewtwo was going to be the only DLC character in the game.
Nintendo would be walking away from a potential goldmine if they just made Mewtwo the only DLC character in the game. If other games like Fire Emblem, New Super Mario Bros 2, and Mario Kart 8 all have their own DLC that earns Nintendo extra money beyond someone buying a copy of a game, then why would Smash not get the same treatment?
Especially since DLC characters in fighting games is a common and popular trend.
I found some of the cuts in Smash 4 to be strange. Why did Wolf and Lucas get the axe despite being pretty popular characters in Brawl and far from being clones?
Because I think some characters like those two either did not make it in due to time constraints or were held back for future DLC. Outside of Mewtwo, I'm sure many people(myself included) would gladly pay to have Wolf or Lucas back in the game. If they got the Ice Climbers to work as well, then that's another character that could be added back in.
It's not a bad model for Nintendo, put out a new character every few months and make some extra cash off Smash 4.
As for Rayman being a DLC character, I think that's real as well. I always thought it was odd that Ubisoft, a company that has had some trouble with Nintendo recently would be the third-party to get a trophy in the game.
Rayman had two trophies in the game! Why does a third-party character who is not playable in any form have two trophies in the game? And if the idea was to give third-party characters their own trophies even if they were not playable then were are the trophies from series like Castlevania, Bomberman, Ninja Gaiden, Final Fantasy, Dragon Quest, Adventure Island, Street Fighter, and other third-party franchises that have made an impact on Nintendo platforms in the past?
Rayman seems to have an unusual amount of content for a non-playable third-party character. Of course, the argument could go that plenty of other non-playable franchises have two or more trophies. But those are first-party game or at the very least games that Nintendo has published in the past.
Why would Ubisoft sign on to have Rayman just be a trophy? I think they wanted him to be playable as a future DLC character. It's a win-win for both parties. Nintendo gets a fairly popular third-party character to sell as DLC while Ubisoft makes some money from the deal, and also have a chance to give Rayman some free promotion that might help out sales of their Rayman games.
I think the Rayman DLC is real.