Adding another question for Field Frenzy: do you feel trick room would be too strong?
Potential Sets:
https://pokepast.es/75d964320f338a26
Trick Room teams will likely have to have a limited amount of automatic setters so that they don't undo each other's trick rooms. Also trick room does not boost the power of any moves. But I feel it's harder to counter trick room than Weather and Terrain. Sunny Day Alola-Marowak in Trick Room sounds broken. Though, Marowak is pretty hurt by magic room and magic room might turn out to be viable due to allowing mons to ignore eviolite, focus sash, choice items, etc. There's also water sport and rain dance that can reduce the power of fire type moves.
I think I'll leave in Ion Deluge and Fairy Lock as moves that can be activated on switch in. They don't really have much of an effect on the meta, but, if it makes coding easier, I don't see why not. Fairy Lock probably makes smeargle and klefki a little better since they don't have to worry about magic bounce mons switching it.
As for moves like reflect,safeguard etc. I'm leaning towards not including them as moves that can be activated on switch in, but I'm open to suggestions.