You guys really need to give some thought to what actually makes a character viable and how they possibly could have potential.
You're going to have to play floaties and mids like ICs, Peach, Samus, Jigglypuff. This game isn't just "You get to play Falcon on FD"
None of the above characters mentioned stand a chance even with lopsided player skill, some of those non-FF MUs are unwinnable.
Pichu for example is just a far worse Pikachu, any strides and developments Pikachu has made Pichu already can't even benefit from 80% of it due to his handicaps and inferior characteristics. Pikachu has exposure on a very high level, so not even MU ignorance is possible for a Pichu (who is just a far easier Pikachu to combo, chaingrab, and kill). Pichu has nothing substantial left, what he does have is not worth a fraction of what could be applied with Pikachu across all MUs. People have already tried. There is a reason you don't see Pichu's at a high level unless it's to troll, there isn't some conspiracy or lack of usage.
Yoshi was not a secret to those that actually messed around with him. It's been long known that he does well against ICs and Marth, even Fox/Sheik sometimes (who have trouble edge guarding him).