Hey,
I think the peppermint and scarlet would be fine together, but not sure about the coral banded. They get nasty when they get bigger. I have no experience with them, but have read about them here from time to time.
Dan'l
I agree w/ Flydan. Get a cleaner shrimp instead. I have two fire shrimp, two peppermints and a cleaner in my tank. They scuffle over food every now and then, but generally they get along fine.
