I'm going to write my detailed speculation from a post in a previous thread on what i think the league could be like.
Episode 1
Arrival, Bringing back reserves, beginning of the tournament preliminaries. Maybe this could be the episode where a Unova Pokémon evolves. I'm guessing it will either be Snivy into Servine or Oshawott into Dewott. They are definitely the two who are overdue.
Ash's Complete League team
Kalos Team
Reserves
Episode 2 Top 256 and Top 128 | Preliminaries 1 vs 1's
Top 256 : Ash vs Jimmy | Pikachu vs Tongari (Pikachu)
Top 128 : Ash vs Random | Noivern vs Random
Not really seen, except a "sizzle reel" of the the main characters advancing.
Episode 3 Top 64 | 3 vs 3
Top 64: Ash vs Trevor
Gible vs Amaura | Gible
Gible vs Dragalge | Dragalge
Kingler vs Dragalge | Kingler
Kingler vs Charizard | Charizard
Talonflame vs Charizard | Talonflame
Episode 4 Top 32 | 3 vs 3 and Top 16 part 1
Top 32: Ash vs Astrid
Bayleef vs Pyroar | Bayleef
Dewott vs Meowstic♀ | Dewott
Dewott vs Absol | Absol
Bayleef vs Mega-Absol | Mega-Absol
Hawlucha vs Mega-Absol | Hawlucha
Top 16: Ash vs Sawyer
Torkoal vs Aegislash | Draw.
Glalie vs Salamence | Episode ends.
Episode 5 Top 16 | 3 vs 3
Glalie vs Salamence | Glalie
Glalie vs Sceptile | Sceptile
Ash-Greninja vs Mega-Sceptile | Ash-Greninja
Top 8 : Ash vs Tierno begins
Totodile vs Hitmontop | Totodile wins.
Totodile vs Vivillon | Vivillon wins. Quiver Dance overpowers Vivillon.
Episode 6 Top 8 | Full Battle
Ash vs Tierno
Unfezant VS Vivillon | Unfezant wins and is recalled.
Torterra vs Politoed | Torterra wins but Politoed uses Rain Dance.
Torterra vs Ludicolo | Ludicolo overpowers it with Swift Swim and Ice Beam spam.
Unfezant vs Ludicolo | Unfezant could not keep up with it and it gets Ice Beam'd.
Muk vs Ludicolo | Muk overcomes it by Body Slamming it stalling it until rain Dance ends and shoots a Gunk Shot upwards and waits until the last minute to move so it hits Ludicolo.
Muk vs Raichu | Raichu wins.
Pikachu vs Raichu | Draw.
Goodra vs Blastoise | Goodra wins.
Episode 7 Top 4 | Full Battle
Ash vs Alain
I don't know which Pokemon to speculate for Alain, but I think this will be the match where Ash uses his whole Kalos team together. I'm sure that the last matchup will be Ash-Grneinja vs Mega-Charizard X. Skip to Alain winning the league against the runner-up. Mega-Charizard vs Chesnaught.
Ash like Sinnoh, ends up being the second best trainer, but in the Top 4.
In my speculation, it gives Pikachu 3 uses, the rest of the Kalos team, 2 uses, and each reserve 1 use each.