I think Rache made lots of teams related to each trainer and rng picks one of them or something.
The rival one wasn't really hard because Tyranitar was the only Jolteon counter, after I killed that with Swampert I just went for Growth sweep ez
Lance was pretty tough but only because it won a speed tie with his Aero facing my Jolteon or I woulda sweep him too
Agatha was just plain destroyed with DD Ttar
Bruno was probably the toughest even though I can't really remember his team (Which doesn't matter cuz they are random anyways)
Lostelle was ez cuz I had Vapo and Skarm and just stalled her to death
So basically, best chance of getting through E4 is bring HP Ice Jolteon with Growth, a DD Ttar, 2 good walls, and some other 2 mons