with the size of your tank I would only go with 1 small fish either a small clown or a gobie but not both the tank is too small to have 2 fish in it due to all the biological demands
I had one clown and it went up and down against the glass for three days non-stop. Took it back. My clown goby is so cool and I think it loves me. He watches the outside of the tank more than the inside. He is one fish I wouldn't trade.
Never mind - I did another search and realized that while the bumble bee shrimp do NOT HAVE to eat starfish - they do have to be fed meaty food daily. Too much work although they look cool.