I too look forward to Fire Emblem Smash on NX. The rest of the roster can easily be replaced with FE characters.

Probably one Fire emblem character would go but Sakurai loves FE. He grew up on it so being able to take that franchise and put into smash is probably really fun for him. I'd also guess Rosalina, Lucas and Bowser jr.

I think Lucina and Robin might be gone in favor of whoever are the main protagonist of the newest Fire Emblem game at that point in time.

As for 3rd party characters.
Sonic for sure is staying.
Pac Man and Mega Man are likely to remain.
Bayonetta and Ryu can go either way.
I doubt Cloud will be back.

Characters I think that would likely be cut are: The DLC chars, Toon Link, Lucario, Wii Fit Trainer, Greninja, Lunina, Pacman, Megaman, Dr. Mario, Dark Pit, and finally, Jigglypuff

Dr. Mario
Lucina/Dark Pit (probably will become Marth and Pit skins)
Cloud
Charizard

You need only look at the Mario Kart series to know Rosalina ain't going nowhere! She was literally the only MKWii newcomer that made it into 7, and she got in before Waluigi, that's saying something about how highly Nintendo thinks of her.

-Wii Fit Trainer
-The Clones except for Dark Pit
-Ike or Robin, I hope not Ike but he is losing relevance fast.
-Megaman
-Greninja or Lucario

Yeah i wonder what is going to happen with those DLC characters........
And im guessing the "Amiibo" functionality of those "removed" characters will stay on the Wii U? Or Nintendo will re-designed the whole Amiibo functionality on the NX?