Unfortunately I can't answer because Wanpre is actually the first Precure I'm watching from beginning to end. Most of the others I've only seen in passing...! I'll always have a soft spot for Precure 5 since it was actually the first movie I watched in a theater here though.

For the same reason as 1 I can't really answer, but I'll give you my favorite transformation instead: Cure Ace! I remember catching that on TV and thinking how awesome it was.

You know how Mayu acts? That's me lol. It was made for me.

I'm not sure. It would be a waste if they didn't, since Satoru is obviously a key member of the team and even as a rabbit we have now seen Daifuku isn't one to be messed with (also Daifuku's human design is so cute...why wouldn't you use that....come on...), but it looks like Nico-sama is probably going to be the extra member so maybe not. Or maybe they'll show up at the end? I wish they'd been given a transformation sequence in the movie at least...