I'm currently working on an additional player character for the game and I think I read somewhere that a character selector would be implemented in a future update (I could be wrong about this.) If this is indeed going to be implemented, should I leave the files related to the tutorial untouched?

As for a future gameplay addition, I would suggest a way to heal the player using their money through a vore animation in the main room of each floor after buying the item that prevents full restores.  This could also work the other way around to sacrifice health for money. I'm not entirely certain how this would affect things in terms of balancing or programming.