This is what I hope will happen in terms of gym leaders:
If 8, in no particular order:
Water: Shizui (blue)
Posien: Homika (purple)
Fighting: Marshel (he was demoted)(red)
Rock: new female leader (orange)
Bug: Burgh (green)
Flying(white)/steel(black): Skyla(a new face among the historic setting)/Jasmine(an old face among the futruistic setting) (grey)
Dragon: Iris (indigo)
Ground: Clay (yellow)
(if ten:
Normal: Aloe
Ghost: Shauntel: (same as Marshal))
Elite Four:
Grass: Cilan, who left his two brothers to run the resturant
Pyschic: Catilin
Electric/Fire: Elesa and a new male, who is insane in the brain(also why the region is still frozen over)
Dark: Grimsly
New Champion: New Villain, who leads a new group with a diffrent person as a figure-head trying to freeze the world over, starting with Unova, leading them from behind the scenes. He lost Kyruem during the main story, who you obtain, but he has replaced him. Mixed, but 4 of the 6 are part Ice types. He replaces Kyruem with the opposite games mascot from the first version.
After you beat the champion, you force him to unfreeze the region, allowing you to visit the past towns. He is then replaced as champion with the main character from the first set who is of your gender.