Mew:
Change Sucker Punch on Mew to another priority move, if he learns it. Sucker Punch is too unreliable.
Latias:
Seems decent, you might want to take off Recover for Grass Knot, though. Or, if you really get into Calm Minding, you will probably find Grass Knot>Thunder.
Rayquaza:
No, stick with...