I have a feeling that,assuming Ridley makes it and gets a trailer, Sakurai is gonna play it out to make Ridley appear as a stage boss to get our hopes down.
Villain trailer Idea: Samus is on Pyroshpere, trying to take on Ganon and Wario. Ridley dashes through the battle. Samus Dodges, but Ridley ends up knocking Wario off the stage. Samus and Ganon continue to fight it out as Ridley shoots fire from the air onto the arena. Having trouble with Ganon, Samus finally fires a FS in attempt to completely vaporize him. It's about to hit him, but suddenly the beam stops at a powerful, invisible force. Mewtwo floats over to the battle, and "Mewtwo Strikes Back" appears. Mewtwo has his spotlight scenes. Screen fades to black. Back to the cutscene, Samus is on the ground, at the mercy of Ganon and Mewtwo, when the two are caught by surprise and Ridley viciously knocks them away. He heavily lands on the stage, walks towards Samus, and roars. "Ridley Sizes Down!". Then Ridley gets his spotlight scenes.