A *very* small scan has just leaked showing us the bottom corner of a new female character: Riine [ree-neh]. The poster on 2ch who linked this image named them as the leader of Team Plasma. In the caption below you can see “Team Leader”. There is also a bit about Iris and a trainer but we’re getting about 1/4 of the text so its nearly impossible to make out.
Also it is confirmed that pikachu DID use ‘iron tail’, it was not a new attack in the Best Wishes promo vid.