>>36018453Sure.
Castform
Sunny, Rainy, and Snowy forms should get a stat boost. If Base Castform has 70 across the board (420), then give its forms 70/70/70/95/95/95 (495). Make it so that weather set up by a Pokemon with Forecast cannot be cancelled out by other Pokemon, barring the Primals and Mega Ray.
Fan Rotom
Give Fan Rotom Hurricane instead of Air Slash, so it's power is on par with its brethren and has more use in the Rain.
Oricorio
Growl is learned at Level 1, Peck and Helping Hand move down to Levels 4 and 6 respectively. This is to make room for a new signature attack learned at level 10. The attack is functionally the same as Revelation Dance but it has a Base Power of 50. Buff its Speed by 5 points. I would suggest to give it Quiver Dance and Petal Dance as an Egg Move too, but no Pokemon in the Flying category can learn those moves.
I'm still debating a few things regarding Cherrim, Flower Gift, and its Sunshine form.