He has returned.
This is a slight nitpick but I wish they would have changed the fields like they did during XY/BW. Having the same exact thing got pretty boring ngl
i may be in the minority here, but them not having special fields involved in this means the pokemon can't use them to tip the scales of battle, and are forced to rely upon their own power.
After all, i know there have been times where using the terrain had too much of an effect on a battle. Like Ash vs Hapu.
As for any changes to the M8?
I would've had someone else instead of Alain, if he and Ash are meant to fight again it shouldn't be in a tournament setting because all people care for is Greninja vs Charizard, and an M8 battle should not focus on just 2 pokemon.
I would also have Leon show case his other pokemon more leading into it besides his Charizard since the way he's been portrayed is basically Alain 2.0