This rumor doesn’t really seem to be that plausible. One user on reddit claims to have broken the data for the latest Smash Bros update and claims that it includes info on at least two new characters that will come to Nintendo’s fighting franchise as DLC. One of them seems plausible. That would be Roy from the Fire Emblem series. He’s been in the game before. That would make sense.
The other one, however, doesn’t seem to jive so much. He claims that there is data for Ryu included. I’m talking the fireball throwing, hurricane kicking karate master from Street Fighter. Yes, he’s in a fighting game, but he doesn’t really seem to make that much sense for Smash Bros. Street Fighter hasn’t been that big a thing on a Nintendo platform in a long time. It’s a strange choice, if true. I would understand more if they were rumoring Ryu from the Ninja Gaiden series. That was a staple platformer on the NES and he’s been featured in a number of different games on Wii U and 3DS in recent year.
I’d hold off on getting too excited about this one until Nintendo make’s a solid announcement.