I know your pain,because I had problems with Angie,but it's all strategy(Honestly,I find Southa a bit harder than the other two):
-Crawli:
I choose Charmander like starter,but I captured Rockruff-Lycanroc,so 3 of his 4 Pokémon were down with Rock Slides
-Angie:
Here,in last versions,she has double Battle with a fast Beartic and A-Ninetales with Aurora Veil,so take a Pokémon with Thunder Wave,Brick Break and something to change the field in a normal Rift Field.
-Ryland:
Take Water-Grass Types and a Pokémon with Knock Off,for Rhyoerior,for example(this I fought one time)