Maractus: Boost both defenses and apply accupressure at the end of every round to all pokemon on your team. This allows it to be a support pokemon, something it fails at usually despite its good defensive ability and cool defensive moveset. This way, it can be a physical tank with fur coat and spiky shield with room still to set up offensively, and still contribute to the fight while setting up spikes in doubles. It also helps it to potentially sweep under chlorophyll,
Pinchurchin Crest: Extends electric terrain and applies a substitute on switch-in, giving it a bit more bulk to compete with galaran corsola.
Corsola: Speaking of corsola... Give priority to defensive moves, like barrier and amnesia, and give it regenerator if it has hustle. Apply leftovers effect.
Volbeat: Make baton pass negative priority, and apply endure effect when using baton pass.
Pachurisu: If it isn't holding an item in battle, have a harvest effect for a random stat-boosting or healing berry. Apply flinch chance to all damaging attacks.
Luvdisc: allow attract to effect any other pokemon regardless of gender, use speed for attack, and apply attract on switch-in.
Kecleon: boost defense and get a new ability based on what type it is:
Normal: Speed Boost
Fighting: Scrappy
Flying: Gale Winds
Poison: Corrosive
Ground: Stamina
Rock: Sturdy
Bug: Compound Eyes
Ghost: Levitate
Steel: Sturdy
Fire: Flash Fire
Water: Storm Drain
Grass: Sap Sipper
Electric: Motor Drive
Psychic: Magic Bounce
Ice: Thick Fat
Dragon: Filter
Dark: Contrary
Fairy: Magic Guard
This lets it set up with speed and then turn it into a game of figuring out what move your opponent is going to use on you to make it have the least effect, and using protean to change to something advantageous. It also incentivizes color change by making you immune to a lot of moves the second time around. Could be fun to trick a choice item onto an enemy and force them to switch or do nothing to you, or disable coverage moves and leave them unable to hurt you.
