Actually, I couldn't care less about Ridley. I want him in because he deserves it.
With that said, why can't Ridley "do stuff"? He's been around long enough to have plenty of moves.
Also transformation characters are gone, so that kills the chances of Toon Zelda switching between Tetra.
Y'know, with how transformation was taken out due to performance issues, I wonder if future SSB's will take another stab at it. Melee didn't have any issues for whatever reason, but Brawl did because it was trying to look much better graphically and maybe the amount of everything the Wii had to process took a toll on performance. With a more powerful system(s), I don't think it'd be an issue.
Who knows, maybe Zelda and Sheik will become one again.
Toon Zelda will probably take the Phantom Slash attack, but I think she shouldn't. Instead, I think Toon Zelda should be able to switch from Toon Zelda and a Phantom Knight like in Spirit Tracks. Why? Well, regular Zelda is more like a powerful mage who's kind of slow while Sheik is more like a thief who's quick and upfront. Toon Zelda could be more like an archer-mage - the most memorable thing about her to me is her aiding Link in Wind Waker with the bow - and like Toon Link, is faster than her regular self. Possessing the Phantom Knight would make her into, well, a knight who's strong, slow, and powerful. This would make her much more different than Zelda/Sheik since she'd be Toon Zelda/Phantom Knight.
That said, if Toon Zelda took regular Zelda's move set albeit modified to fit her stubby legs and arms while Zelda becomes more like Twilight Princess and Hyrule Warriors Zelda who used a rapier, then Toon Zelda/Tetra would work. Tetra would be the first knife-wielding character so Tetra being a clone won't matter. Speaking of which, I think the team didn't want to include Tetra since if Toon Zelda/Tetra was supposed to exist and transformation being an issue, then including them now might not be a good idea. Hell, it'd be worse if they included them, but Toon Zelda was Tetra's Final Smash - I don't know, Toon Zelda could shoot a Triforce beam or something.
Toon Sheik makes no sense besides being an adorable character option.
Toon Ganon is already unique... Man's got a badass robe and dual swords.