>>31787418>>ORAS gives us the multiverse theoryNo, ORAS tells us there's another universe. Multiverse implies infinite number of universes, one for each possible outcome. That's not been proven or even hinted. In Pokemon, Palkia creates dimensions. There's high chance there's only a limited number of them.
What's more, unlike how multiverse theory would work, the universes we know about are all almost completely identical.
>ALL main gamesBoth Sun and Moon are. Just because there are two universes for those two doesn't mean the same is the case for all of them. At least, there's no proof there is. That is just your headcanon.
>protagonists and rivals are canonEven if all main games are canon, this is completely false. In SM, even when you visit the other universe, the other version, the protagonist is the same. That implies that only one protagonist is canon. It also fits the narrative of the universes being almost completely identical.
So no, there isn't a universe with Leaf as the protagonist. There isn't one with Chicken. There isn't one with May.