The scene with Perfect Zygarde rising,
the trainer in question is Red from ORIGINS!
The HYPE is real!!!
Possible arcs:
1. Green defeating Elite Four, before he reigned champion
2. Ho-oh reviving Raikou Entei and Suicune
3. Red somehow has an involvement with Zygarde!? (epic cutscene with light shining through,
all the way over the overworld).
The rivers along the overworld seem reminiscent of Kalos, not Kanto
(the cutscene with minecart riding and Noivern attacking them could indicate Terminus Cave)
4. Looker sidequest?
5. Lance VS Red Gyarados
6. Heatran Battle on Battle Arena!
7. Regigigas Battle! (temple in DPPt)