In my LFS they had a 5 gallon tank with betta in and 2 shrimps, I actually watched the shrimp walk over the betta literally and the betta didn't even flinch! They have been in the tank with him for a while - Im practically in there everyday.
Danios are not good tankmates for Bettas either. They tend to be fin nippers. Some shrimp have been known to attack and kill fish. Those claws scare me. I wouldn't want a shrimp anywhere near my Bettas!