Saikyoshi
Smash Master
I wouldn't say Snake is out of the picture yet since Kojima explicitly said that Sakurai still has permission.
You know, this leak opened a very big door again : the possibilty of other DLCs in the future.
As we can see, Rayman was technically announced by his trophy. Mewtwo also got his own trophy in the game, but still is a DLC. By the trophies, the leak opened a possibilty of actually having back some veterans.
Here's a probable list of them :
High : ,
Low : , , , ,
Inexistant : , ,
It's a personal list, but some of them do make sense. For Lucas and Wolf, the representation number, as well as the trophy of both of them give them the highest possibility of a comeback for them.
For the "Low" tier, Roy can't really enter due to being a simple clone of Marth. His place has already been taken by Lucina and ironically a Koopaling. Squirtle and Ivysaur could return thanks to their originality, but the representation of Pokemon is already enough. Same goes for Pichu, but even lower due to being a clone. Young Link has the same reason as Roy.
The "Inexistant" tier is obvious : Snake won't return for sure, and Pokemon Trainer and Ice Climbers won't return due to technical limitations by the 3DS.
In short : thanks to this leak, the DLC door is reopened, but only for some characters.
And Popo might come back if reworked somehow. I personally wouldn't mind SoPo/SoNa.