Which is an idea but that is one big pet, in that other thread.I'll confess I don't know Pokemon that well, played once. But the idea of "Pikachu ... I choose you" has gotten to me, so my assumption is that a Pokemon Trainer style Summoner would have multiple options for creatures to summon (Gotta catch them all), but would only have one "in play" at a time. Maybe spiking to 2 or 3 at high levels, but the base assumption is one at a time.
this is to discuss summoners who may have two or three companions plus a mob they whistle up with magic.