MasterofArcanine
Pokecollection Maste
Having both Arcanine and Rapidash retypings is pretty much overkill. However, I think Arcanine and Rapidash could just take the Megavolution to get a retyping. Like how Mawile only get fairy typing through megavolution.
Uh its stated that Normal Mawile has the fairy typing too? The only one who adds a Typing through Mega Evolution is Ampharaos (as far as we know-its never been stated that normal Ampharoas doesn't have it too)