Why are you choosing a frame then ?
Well, animations in the 'chooser' is no problem.
For the actual play character. I would not organise the animations in folders as you do. Even in folders the animations can not have the same name. You end up with, if you want to dynamical access the animations, something like "walk1" .. "walk2" .. "walk3" They are dynamical accessible by "walk"&str(CHAMP) as expression. Still, a burden, easy to make mistakes. And if you replace one 'from source' all the animations (i think) get replaced.
I would make a different object for each character. Put them in a family. Make them global.
Before going to the next layout i would spawn the right character on a global layer. Now this character will just be there in every level on the layer with the same name as that global layer in the chooser layout. And keep its instance variables when going to a new layout level.
Each event in the actual game events will address the family, ofcours. Very easy if you want to add characters later. Just add it to the family.