glad to hear that everything has worked out well for you despite the loss of your Louisiana milksnake. They are a beautiful species and it is sad to lose one even when you have had it for a short time.
I just read through this thread and wanted to offer a couple comments to the original situation. While I am sure having just eaten a rather large meal did not help her situation, I would caution you about placing transport containers on the floor of a vehicle when travelling - it can often be the hottest place in the car (heat from the engine, drive train and exhaust system coming through a rather poorly insulated floor). Not sure if they were on the floor on the way back but you mentioned it on the drive there. A covering over the tubs may have reduced ventilation in addition to this and prevented cooling from the air conditioning system from circulating through the deli cup. I think your comment that the snakes felt warm when you handled them is a tip off that overheating may have been a factor. Most of ours thermoregulate to about 82-85 degrees body temperature, which feels cool to people because our body temp is almost 99 degrees. If these guys felt warm to you, they were likely well over 100 degrees, which - if prolonged - could have been a factor. Not sure this was the case, but something to consider in addition to the huge meal - and something to avoid in the future - especially with such little snakes that seem more limited in their ability to cope with stress.
Glad to hear you have a replacement and congrats on the Arizonas - they are one of the most beautiful species.