They could easily switch up Young Link's move list if they made him Celda Link: Grappling Hook, Cane of Pacci, Gust Jar, Pegasus Boots, Bombchu, Skull Hammer, plus any items he uses that older Link isn't using. Final Smash could be a Four Swords-style thing.
Also, while Dark Link may not have red eyes in Ocarina of Time, he did in Twilight Princess. Since Link & Co. have been remodel to fit this games style, it only makes sense for him to sport them.
Also, looks like Saki Amamiya from Sin & Punishment: Successor to the Earth is now in as an Assist Trophy. Nice to see another relatively obscure character getting in on this.