Emergency shelter for disaster response

I have been designing a reptile disaster animal shelter. I volunteer with a reptile rescue and we work with a disaster animal response team. Oddly they handle cats number one and reptiles number two then dogs. (dog owners are usually established and have friends whom also have houses or other dogs so they often look after them selves) Cats are not very hard. Reptiles are very complex.

Here is the question. I have a design that works to hold a reasonable stable ambient temp it will hold a number of animals. What is a reasonable temp that will be tolerable by the widest range of species? I have been using 80ºF as a base temp Royals and corns tolerate this well beardie and iggies too.

What species is this totally unacceptable for?

Please keep in mind this is for a short term (hours to 2 days max) emergency housing, not perfect husbandry. The average winter temps here are -5ºC and summer over night are 20ºC so some sort of heated unit is needed and the back seat of a idling car is a poor option.