If possible, will there be a way to switch routes your currently on if for example, you messed up on a route and like to restart it without having to make a new game for it?

Nothing confirmed yet, also unlikely as the developer likes to keep the game in a way when you make the wrong choice you have to live with it. Though this can be easily mitigated by regularly saving from your room, allowing you revert back to a save and correct your mistake. Personally I am hoping for a new game plus mode which when you complete the game one way it is a lot faster to progress another.