If you want Cel-shaded Link, I say take out Young Link.

Take out Pichu for Raichu, and add Wigglytuff as well.
And Blaziken would be cool too.

Jeff, Paula, Poo and any of the forms of Starman(maybe each variant is a costume? Like Ghost of, DX, Super, and regular?)

Pit from Kid Icarus.

MetaKnight and King Dedede.

Oh and some characters from Mario and Luigi. That games awesome.