Just keep in mind, as much as /v/ can spout out a lot of fake things, every once in a while you can get an actual leak. It's like looking for a needle in a haystack, if said haystack was put on top of a pile of manure. Last time that happened, it was for one that everyone missed during the Box Theory incident (mentioning Ken, Incineroar, and Piranha Plant (that was still in development, since a kart was mentioned)). Also said leak threads get deleted automatically anyway when they reach the last page and aren't bumped.
As far as supposed leaks go, it doesn't seem too outrageous. Normally it would be for "insert fan-favorite character that's not the lead here!", but this one sounds like what the staff would do. The only outrageous part is the alts, but even then it does seem doable depending on bodies chosen and the time allotted. Besides, we don't know whether Spring Man will be 1:1 in overall abilities or not, seeing as the only thing specified for the ARMS fighter is stretching.