I'm a bit confused as to who are Trial Captains, who are Kahuna's and who are E4, who's the Champion (there seem to be some overlapping between them all?), could someone clarify who are who haha?
Captains are the five we know about + Mina (Fairy) and the unnamed Dragon one.
Kahunas are Hala (Fighting), Olivia (Rock), Nanu (Dark) and Hapu (Ground).
Elite 4 is Olivia, Hala, Kahili (Flying) and Acerola (Ghost). Kukui is the champion.
The team listings are here if you wanna poke through: http://pastebin.com/vkaZNTra
There is none, but there is a high-leveled Dragon-type trainer named Ryuki.
Oh, that's odd. Maybe Lillie guides us through the trial or something.