I don't know how I feel about some Unovan mons getting regional variants in this region, considering what they're primarily based on and the time period that the game is set in. Stunfisk I can kind of get being that it is based on a flounder (which are endemic in England as well as the U.S) but these other two.... ehh....
GameFreak is notorious for retconning Pokémon lore. It started with Gen 2, and consecutively every generation after. The ORAS Delta Episode is basically GF saying we can do whatever we want without worrying about the lore.
Pokémon having new types? Multiverse.
Trainers don’t age with the timeline? Multiverse.
Regions interacting with one another but don’t share Pokémon discoveries or distributions? Multiverse.
Key characters or places not existing? Multiverse.
Pokémon from a faraway region existing in the past of another region? Multiverse.