I've been doing some testing on the trainers that appear before battle 31 in the super modes just out of curiosity. This information probably isn't overly useful for most of us but I figured I might as well share.
Here's the list of trainers that appear early on in the Maison, along with the teams they use.
Set 1 Trainers
These trainers always use Pokemon with IVs set to 19. I've separated the list with a line. Trainers above the line only appear during the first 10 battles. Trainers below the line can appear from battles 1-20.
Backpacker Erroll (1st set B)
Backpacker Seamus (1st set A)
Garcon Basim (1st set A)
Garcon Caleb (1st set B)
Hiker Abseil (1st set Rock, Ground, and Steel types)
Hiker Deck (1st set Rock, Ground, and Steel types)
Lady Aline (1st set B)
Lady Francoise (1st set A)
Lass Eva (1st set Normal and Fairy types)
Lass Lauren (1st set Normal and Fairy types)
Poke Fan (M) Antony (1st set B)
Poke Fan (M) Rhett (1st set A)
Poke Fan (F) Dierdre (1st set B)
Poke Fan (F) Ophelia (1st set A)
Preschooler (M) Cody (1st set B)
Preschooler (M) Preston (1st set A)
Preschooler (F) Ava (1st set B)
Preschooler (F) Madison (1st set A)
Rich Boy Auric (1st set A)
Rick Boy Kasper (1st set B)
Schoolboy Fritz (1st set B)
Schoolboy Schuyler (1st set A)
Schoolgirl Athena (1st set A)
Schoolgirl Kaya (1st set B)
Tourist (Old) Edirne (1st set B)
Tourist (Old) Marbella (1st set A)
Waitress Char (1st set B)
Waitress Tilapia (1st set A)
Youngster Nathan (1st set Normal and Bug types)
Youngster Pablo (1st set Normal and Bug types)
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Butler Elias (1st set A)
Butler Joshua (1st set B)
Butler Jude (1st set Mixed)
Chef Dariole (1st set Water, Fire, and Grass types)
Chef Florentine (1st set Water, Fire, and Grass types)
Chef Jus (1st set Water, Fire, and Grass types)
Fairy Tale Girl Aurore (1st set Normal, Psychic, and Fairy types)
Fairy Tale Girl Jeanette (1st set Normal, Psychic, and Fairy types)
Fairy Tale Girl Sylvia (1st set Normal, Psychic, and Fairy types)
Maid Beth (1st set B)
Maid Joelle (1st set Mixed)
Maid Paige (1st set A)
Punk Guy Oberon (1st set Poison and Dark types)
Punk Guy Pan (1st set Poison and Dark types)
Punk Guy Triton (1st set Poison and Dark types)
Punk Girl Ariel (1st set Poison and Dark types)
Punk Girl Rhea (1st set Poison and Dark types)
Punk Girl Titania (1st set Poison and Dark types)
Rising Star (M) Jamie (1st set B)
Rising Star (F) Tilde (1st set A)
Set 2 Trainers
These trainer always use Pokemon with IVs set to 23. They appear during battles 11-30.
Artist (M) Gray (2nd set A)
Artist (M) Jasper (2nd set B)
Artist (M) Rufous (2nd set Mixed)
Artist (F) Carmine (2nd set B)
Artist (F) Scarlet (2nd set Mixed)
Artist (F) Sienna (2nd set A)
Beauty Lucinda (2nd set Normal, Dark, and Fairy types)
Beauty Lucy (2nd set Normal, Dark, and Fairy types)
Rising Star (M) Giacomo (2nd set B)
Rising Star (M) Guillaume (2nd set A)
Rising Star (F) Carol (2nd set B)
Rising Star (F) Lena (2nd set A)
Roller Skater (M) Manuel (2nd set Electric and Flying types, Empoleon, Flygon, and Floatzel)
Roller Skater (M) Rory (2nd set Electric and Flying types, Empoleon, Flygon, and Floatzel)
Roller Skater (F) Cleo (2nd set Electric and Flying types, Empoleon, Flygon, and Floatzel)
Roller Skater (F) Sierra (2nd set Electric and Flying types, Empoleon, Flygon, and Floatzel)
Worker (Blue Hat) Arnau (2nd set Rock, Ground, and Steel types)
Worker (Blue Hat) Leo (2nd set Rock, Ground, and Steel types)
Worker (White Hat) Esteban (2nd set Rock, Ground, and Steel types)
Worker (White Hat) Jules (2nd set Rock, Ground, and Steel types)
Set 3 Trainers
These trainers always use Pokemon with IVs set to 27. They appear during battles 21-40
Beauty Apollo (3rd set Water and Ice types)
Chef Dylan (3rd set Water and Ice types)
Furisode Girl (Pink) Fleur (3rd set Eeveelutions)
Furisode Girl (Blue) Marilla (3rd set Eeveelutions)
Gardener Florian (3rd set Grass and Bug types)
Gardener Giorgi (3rd set Grass and Bug types)
Madame Elizabeth (3rd set B)
Madame Marie-Noelle (3rd set A)
Monsieur Frederik (3rd set A)
Monsieur Harris (3rd set B)
Pokemon Breeder (M) Ewert (3rd set B)
Pokemon Breeder (M) Jovann (3rd set A)
Pokemon Breeder (F) Noemie (3rd set B)
Pokemon Breeder (F) Zoe (3rd set A)
Tourist (M) Heathrow (3rd set A)
Tourist (M) O'Hare (3rd set B)
Tourist (M) Sydney (3rd set Mixed)
Tourist (F) Florence (3rd set Mixed)
Tourist (F) Odessa (3rd set A)
Tourist (F) Valencia (3rd set B)
General Notes
- Refer to R Inainmate's post to understand the As and Bs. Mixed means that they use Pokemon from both groups. I'm not sure if they can use literally all the Pokemon from those groups, but I don't think I've ever seen any of them use any 6th gen Pokemon, or any starters, so take that as you will.
- Many of the "specialised" trainers are similar to some of those seen in battles 41 and over (Chefs, Furisode Girls, Workers, etc.). However, there are some unique ones too, like the Gardeners, Fairy Tale Girls, Youngsters, and Lasses.
- The 1st set Punks are Dark/Poison specialists. They don't specialise in Fire like the 4th set ones do, and the only Fire-type you'll see them use is Houndoom.
- The 1st set Hikers don't specialise in Fighting-types like the 4th set ones. They are Rock/Ground/Steel, like the Workers.
- The 2nd set Roller Skaters are odd. Most of the time they use Electric/Flying as expected. However, I've also seen them use Empoleon, Flygon, and Floatzel occasionally, similar to how Chef Andrei uses a Meganium on his Hail team. Those are literally the only non-Electric/Flying types I've seen from them. I don't know why they use those ones in particular. I guess Flygon can be explained away with Levitate, and Empoleon 2 has some Flying moves in its moveset (Drill Peck and Featherdance). I have no explanation for Floatzel though.
So that's that. Hopefully I didn't miss anything.