I wonder if they were literally close together (like within a few feet) or were they found in the same area, but further apart. Respectfully, I just can't see three people freezing to death at the exact same time. If one froze to death, surely the others would go to get help or try at least. They were only three miles from their car which would have provided some shelter.
ETA - it also wasn't that cold. https://weatherspark.com/averages/30205/10/8/Eufaula-Alabama-United-States
There's a ton of discussion a while back on one of the Jamison threads re: hypothermia and the weather conditions when they disappeared. It really doesn't have to be that cold, certainly not freezing, to die from hypothermia.