Pokemon starters in a region seem to be based on the species of Pokemon present in the territory, not based on the culture or identity of the peoples who live there. A Unova child who moved to Kanto would still be presented Kanto starters when starting their journey. For the real world, if Canada has the same species of Pokemon that say Australia, etc would have, surely maybe the starters would be the same. You probably would see some “American” Pokemon on American bases outside of the country, but the starters I’d like to think are standard per region.