Use coolers to move the fish. Put air tubing through the drain, silicone it in place, and make sure noe water leaks, and hook the air tubing up to a portable air pump. I move stingrays this way and they were in it for two days.
If you want to add heat pack, just line the cooler with a 50 gallon trash bag, bring the tubing up the side and into the bag, and just loosely tie it shut, enough so water won't come out, but enough so that, air can escape. Then just place a heat pack on top of the bag, but I don't think you will really need one for ocars.