Ash
Greninja ends up happening vs Olympia when Frogadier has trouble with her Meowstic.
* [ Water Shuriken | Night Slash | Aerial Ace | Double Team ]
Fletchinder's could play a role in hatching Ash's egg by having its natural ability, Flame Body take effect. Then it could evolve into Talonflame to help protect the egg about to hatch from TR.
* [ Heat Wave | Flame Charge | Acrobatics | Steel Wing ]
Hawlucha can maybe get a few episodes of development, hard to do with no evolution-line Pokemon.
* [ Flying Press | Karate Chop | High Jump Kick | Dual Chop ]
Goomy could evolve between its capture and Clemont, then perhaps on the way to Laverre City evolve during a storm episode to protect Ash from the swamp Pokémon.
* [ Dragon Pulse | Dragon Tail | Muddy Water | Power Whip ]
In this speculation, Skiddo is his elemental trio base form Pokemon, like Corphish and Buizel. It also hatches from Egg before the gang reaches Lumiose City.
* [ Vine Whip | Seed Bomb | Bulldoze | Zen Headbutt ]
Spinda doesn't really mean Spinda, in this it just represents a past generation pokémon he could get that will have a gen 7 evolution like Aipom. Besides he hasn't caught a Pure Normal type since Aipom and hasn't kept one since Snorlax.
* [ Secret Power | Teeter Dance | Copycat | Psybeam ]
Serena
Braixen staying as is for performances for now. It could evolve in Serena's future special or when he's gonna leave the cast.
* [ Flamethrower | Fire Spin | Hidden Power | Psychic ]
Pancham is her Psyduck, Skitty, Buneary, Axew... her cute Pokemon that won't evolve for marketing.
* [ Karate Chop | Sky uppercut | Dark Pulse | Stone Edge ]
Shauna tells Serena that she should raise Chespin as it loves to perform. Episodes later, Serena catches a Pokémon that hates to perform and prefers playing around with Clemont's inventions. Trade happens.
Chaos in forums ensues
* [ Vine Whip | Grass Pledge | Pin Missile | Take Down ]
After meeting Lisia who promotes Pokemon Contests, Serena wins an Egg containing Mudkip and it evolves into Marshtomp and then Swampert. Her 'powerhouse'.
* [ Scald | Mud Bomb | Hammer Arm | Ice Ball ]
Clemont
At Lumiose Gym
Honestly I can see this being a Buneary or Snivy in which it stays stale through its run.
* [ Double Slap | Double Team | Mud Shot | Dig ]
Dedenne is kept for Eureka and doesn't really battle.
* [ Thundershock | Nuzzle | Play Rough | Tackle ]
Luxray becomes his traveling main, while Heliolisk is his Gym main.
* [ Discharge | Wild Charge | Swift | Iron Tail ]
Rotom is the Pokémon that Serena accidentally captures and Rotom takes a liking to Clemont and his machines. Rotom actually provides some stability to his machines which cause it to not short circuit as often as they do. This Rotom is a bit timid and calm. It wants to prove itself useful after so many people in the town hated it for misunderstanding its enthusiasm to help (and failing) for mischief.
* [ Charge Beam | Shadow Ball | Charge | Special Move+ ]
+ Clemont carries a small appliance that Rotom can use before going into battle, Clemont decides which one he will use before going into battle.