>>28071209the alolan forms we've seen so far are ones that probably outright replace their older forms in the region so no regular marowak, exeggutor, ninetales, raichu, sandslash or persian in alola.
but there's always the potential that some of the ones we might get in the future will be revealed to ones that coexist in the same region (but different islands) with their older forms. we still have three months to go, so we don't know for certain the full limits of alolan forms yet and i don't know why people are pretending we do when they say that this pokemon was in a trailer so isn't getting a form.
maybe the next news reveal will cover something like "island differences and version differences". or something like that. and if rockruff's rumored evolution method is true, that could be covered then too i guess.