No, the only thing that can potentially happen is you can miss out on moves if it evolves after it would learn them. You can fix this, if you need to, by going to the Move Reminder as long as whatever evolution it is currently in could have learned the move via leveling up. EVs are set once you get them unless you lower them with berries, and stats adjust to being Base stats of the form it is in, plus IVs plus EVs.
