Don't put shipping water in main tank, with the exception of the cucumbers, starfish, or anemones, which should not be exposed to air.
Float all bags in tank (or sump) for at least 30 minutes to bring to equalize temperature. Hermits can be grabbed out and dumped in unceremoniously after that.
Snails should have 1/2 cup taken out of bag, 1/2 cup tank water put in, every 5 minutes or so, for about 30 minutes, then, can be grabbed and thrown into the tank.
Cucumbers and starfish need to be drip acclimated over about 2 hrs (same process as snails but for 2 hrs). In this case, pour most of water out at the end, and pour critters into tank.