Ophie
Salingerian Phony
Are you able to go into the waiting rooms to rotate your teams when you rebottle the champion cup? I tried battling again & I was sent straight to the battlefield.
In the Champion Cup Rematches, you should be able to swap your team members around between battles. I've done the rematches many times, and I don't remember ever being thrust from one battle to the next without a chance to pause.