And, in the opening Phanpy has one scene on it's own attacking, followed by a frozen image of the group. The other potential evolutions get little more than that, in fact. That can easily be updated, and they've done it before. They'll make a 20-odd minute episode that has no purpose and is immediately forgotten, so 10 seconds of footage that will last for 50 episodes or more and help the continuity isn't a daring investment.