Super Smash Bros. Ultimate

[Moonface]

I can't tell if their moves are different outside of their Final Smash, but the fact that Mythra sliced the bomb apart in the trailer and not Pyra gives the impression they have different moves. Otherwise Pyra could've just sliced the bomb herself. Either that or it's meant to reflect the characters in that Pyra panicked, but Mythra is more composed to know to slice that bomb. Hard to say when I don't know much about the characters since I didn't play XC2 and can't even remember much of what @ShiraNoMai did in it.