>>51984147For all intents and purposes they're separate Pokemon completely unrelated to the originals. An ordinary Donphan can't turn into Future or Past Donphan, nor can Future or Past Donphan turn into ordinary Donphan. Future and Past Donphan have their own pokedex numbers are are counted in every way as separate Pokemon.
Or, to put it simply, the *only* connection Donphan has to Great Tusks and Iron Treads is that it kinda looks like them.