i've been doing a little bit of these stuff so maybe i can add in a bit.
if shipment duration is > 12hours
maybe you want to try to bring along a smaller cooler with some ice to top up into the larger cooler once in 12hours (but never add too much ice because a little bit too much can cause the temperature to drop excessively).
if my location is too far, i usually check in to a hotel and bring along artificial ice liquid and freeze it into ice before i pick up the 'commodity'.
i like the increased protection idea 'plastic bag + foam + styrofoam + cooler'
plastic bag - leak prevention
foam - shock absorption
styrofoam / cooler - holding & temperature preservation
if distance is too long and you are determined not to do this twice then cooler is better idea.
I use Coleman coolers & artificial ice liquid, large enough and works for me.
Also, if distance is too far, I try to bring along another cooler with sea water, just in case....... but it will be a operation to transfer sea water into a plastic bag in the midst of your journey, to do this you really need to plan carefully because you don't want to spill or lose the poor creature to die in dryness.....
All the best and treat them (these creatures) well!