Use a heart scale on Donphan for Magnitude or level it up to learn EQ and use common candies after.
Charizard I think is ok, Ampha too, IRDK about Fearow, Meowstic good Floatzel maybe u need something better than Rock smash
And maybe some support items. And try to use diferent pokemon to take down some of hers, use some potions, Candies etc. I think you are great