I don't like the idea of Final Smashes involving calling in their nemesis to do damage. Like, if Bowser called in Mario to fight for in while he took a nap or something.
I also don't like the idea of reducing Jigglypuff to nothing but "The Pokemon that can do nothing but use Rest"
A massive singing attack would be cool though, reflecting the anime and her moveset. Puff Up's decent though, just kinda meh. Maybe whe she deflated she blew everyone away farther.