Incidentally, I beat them without losing any pokemon unintentionally - I had L12 Starly on the left, L12 Oshawott in the middle, and L11 Torchic on the right - first I focused down the Bulbasaur in 2 turns, then the Charmander (when my Oshawott got hit a lot I used my Torchic to use potions on...