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. The caption does indeed state that this character is indeed some kind of mysterious leader and is after Iris.
Also it is confirmed that pikachu DID use ‘iron tail’, it was not a new attack in the Best Wishes promo vid. Though we already new this since Ash shouted it aloud in the trailer after the latest episode.
ps- More news as it breaks.
pps-Ozy and Kriffix think its fake :p
ppps-Thanks to Keanno for pointing out that the would-be Leader is in fact a cheap edit of an existing character.