I hadn't seen that one before. I don't think it's all that believable. Mostly the statements on Dixie Kong and Ridley. I mean, if Ridley is playable, there's no reason for him to be a hazard. And unless all those Alfonzo jokes end up being true I don't see the devs having two different Ridley's on the same screen unless it's a second player picking the other Ridley. And we don't have any reason to believe he's a hazard since we've seen so many damn pictures of the arena already. Compared to the other levels, where their gimmicks were shown off relatively soon.
As for Dixie, it's mostly the swap out gimmick. Wasn't Diddy already shown using all of his special attacks? How would he switch with her? Is there a new input we don't know about? If she's in, Diddy doesn't need her to piggy back off of him now. He has his own moveset. And Dixie likely has enough to work with as a fighter.
I guess having Anna might be unlikely, then again I don't know much on Fire Emblem. Doesn't she have multiple incarnations in most of the series? It would make some sense to add her if that's the case.
And last but not least, would be Jack Frost. Now, I'm not one of those guys that thinks each company only gets one third party character. It would honestly be easier to get two characters from Capcom and Sega, than say one from Capcom, Sega, Namco, and Konami. And Jack's another Sega rep now. But really don't the character as iconic enough to warrant an inclusion in Smash. And if we did get another Sega character, he'd likely be competing with other popular Sega characters. It's not an impossible choice, but I can't see him being one of the top choices either.
Sorry if this has been discussion was beaten like a dead horse. This was the first time I've seen this "leak".