It would be 100% easier than having salt water fish.
I dont know much about live rock but I know that you can put inverts into it and they will be very happy.
buuuuuuut, YOU NEED TO MAKE SURE YOU HAVE THE RIGHT SALT CONTENT and make sure every other aspect (pH, ammo, etc) is at the correct level, or your shrimp WILL die, Fire shrimp are sensitive as well as lower grade shrimps.
honestly any salty creature is sensitive to water quality, but its definitely easier than having salty fish!!!!
I SAY YAY INVERTEBRATES!