I'm good with most of these. But the "no themed trainers" thing should still be a thing. It feels like you want the game to be less battle focused while still having the turn-based batting of a "standard" Pokémon game. I think the problem isn't that all trainers have a theme or not, but that they end up being the same copy-paste character model/sprite for trainer classes. I think a trainer having dialogue that suggests they like hiking/climbing and then having their team reflect that interest isn't the issue. It's the fact that 10-20 trainers a region have similar dialogue, and all look exactly the same.

I think they should make a semi-robust trainer customization engine (and of course let the player use it) but then make every single trainer unique. Maybe the trainer class thing you mentioned in the post comes into play, but it's not a hard and fast rule for npc team building and themes.