Hm, sounds possible. Maybe if you evolve the Jagged Ear Pichu, it will become a Jagged Ear Pikachu, or Raichu. Hm, I think this form isn't only exclusive to the event. I think there will be other ways to get a Jagged Ear Pichu, and probably with a different gender too. One thing is for sure, since there was a Pichu hiding behind the shrine, that must mean that the shrine will be used later in the game. So Celebi will probably be in the game!