I forgot to update this thread... We had a good experience with TSA. They were very interested in what the creatures were and we didn't have any issues. It did take longer than usual to process us, so keep that in mind when planning your travels.
When we got to the scanners we announced to TSA that we had "live animals in water", they then processed the animals separately. We went threw the security line normally. The animals were taken out of the cooler bag, inspected, swabbed down, and the cooler bag put through the X-ray. We chatted, joked, told them what they were, repacked our critters, and went on our merry way.
We brought threw a small selection of crabs, snails, and shrimps. All were in bags containing 3 oz of water. As
@REEFIN RIOS mentioned, it would be a good idea to place a small snail or hermit in with corals, just so the average layperson can see for themselves that something is alive in each bag.
Maybe we'll try some small fish next...