Derrick
I do not fish with eels all that often but have used several 1-2 day old eels that were still alive. Make sure you get some good seaweed, like the stuff you see on the rocks of the canal and keep them cool.
A month ago I fished with eels that were two days old. Out of 12 only three had died. The other 9 were very much alive and in fact 3-4 were let go at the end of the day and happily swam off. The keys are cool, damp, dark and you should be fine. Don't leave them outside at night, that is probably a little too cool this time of year.
Scott