Maybe Team Plasma did not reveal themselves because they were argueing their believes on getting trainers to release their Pokemon and split in two One would try to scare people with thoughts on having Pokemon on side led by N, and the other will scare them with their threats of stealing led by Ghetsis.
My Predictions For The Protagonists:
Ash: Pilachu, Greninja, Talonflame, Hawlucha, Tyrantrum, Trevenant, Goodra(leaves until the league)
Serena: Braixen, Pancham, Mudkip, Noibat
Clement: Bunnelby, Quilladin, Luxray, Krokorok
Bonnie: Clemont's Dedenne(caring for)