Tetra: Balancing out the Toon to 'realistic' Zelda styles, Tetra fills in for forbidden 7 Zelda
Toad: Sneakily adding in to replace Captain Toad who was kicked out for Forbidden 7 reasons too.
Ike: Fire Emblem badly needed another character and Ike is a pretty cool guy.
Mewtwo: Number one most wanted character in the world. Probably not gonna happen yet again, but here he is.