>>35574275But how is it even a spin-off at that point? If it introduces a ton of stuff into the main canon.
Coliseum was spin-off game. It's non-canon, but had it's own mechanics and story, yet nothing contradicts the main games or new is permanently introduced. Other canon games have already introduced multiple universes and different timelines, to explain why the timeline of events (and discovery of Pokemon) don't add up, so them having a weird timeline in this game isn't inconceivable either, but a total contradiction to the original games would.
So, why on Earth would spin-off games introduce new canon Pokemon and other characters into the game and, going by the leaks, why would a spin-off game be a sequel to a previous installment?