To be honest, I have to say I don't see much of that, specifically: Vanilla does hesitate but from what I read it's because she wants to protect Pikachu (or maybe protect herself from his possible second death) and not because the advice came from someone she doesn't like. Besides, I don't really see a decrease in animosity, or at least there is no significant improvement of how Vanilla sees Adrienn (not considering the relationship point she gave them), in my opinion she just surrenders to the opponent's ideal of trainer.
To be more specific, she never tells them they could be right but ins