I had an agressive tank that had a lot of the same fish. I put in crabs and snails. I tried to get the biggest ones I could get to try to keep them from becoming a snack. I did lose some but the ones that made it became very good at playing dead when they were noticed by the fish. I had a trigger that would keep knocking the hermit over to get at it, but the crab would just stay put until the trigger lost interest and then would make his escape.
I would say go for the hermits, but plan on losing some if not half.