22 characters makes sense in a game like this too. The fact that we oh so conveniently have Spongebob and TMNT stages being three in count with only three reps is extra suspicious to me.
I'm not saying 22 characters doesn't make sense; what I AM saying is that we having nothing to base this off of outside of that one teaser trailer...and that could potentially mean nothing.
Regarding "Stage Theory" being 1:1, what weirds me out/makes me tilt my head is that the vast majority of stages could be considered home stages/stages that the character in question is associated with, but then we get to the Spongebob and Ninja Turtle stages, and suddenly there's a discrepancy between at least one of the characters present or one of the stages (i.e. Flying Dutchman's Ship and the Technodrome don't have any character that could be associated with them).
I don't know, just compared to how the rest of the game's stages have been presented, it strikes me as weird that suddenly there's two stages that have no correlation with any of the playable characters from that series. And it's this that makes a part of me wonder if "Stage Theory" could potentially be one giant coincidence.
I guess we'll just have to wait until Ren & Stimpy and/or the Avatar characters (however many there actually are) are revealed to know for sure.