Is this too much to bring to camp in a toiletry bag?

You don't need many hair ties, just put 2 round your wrist. Borrow toothpaste off one of the other girls when you get there or just buy some from a shop. You don't really need mouthwash, you can live without it. You could probably get away with just one hair serum if you use it sparingly, and wear your hair up most of the time.