@MGMillie Great question! I love that you focused on the safety-side of cold camping with your pups!
My former pup, Tahoe (RIP) and my current pup, Hank, both LOVE camping and we will take them camping even when it gets below freezing. I 100% agree with @REI-RachelL that knowing your dogs will help you make the best decisions for your pups. Both Tahoe and Hank have a synthetic (human) sleeping bag (since it's easier to clean than down and keeps it's warmth when wet since both are/were water-loving dogs), but how I put them in it is different. Tahoe was a skinny, cold-natured mutt, so she was always zipped up to her neck with 2 closed-cell foam pads below her. If it was really cold, we would bring extra blankets for her. She absolutely loved it.
Hank, on the other hand, is well.... a tank, so he tends to overheat unless it's close to freezing. He still uses the sleeping bag and closed-cell foam pad, but I will only zip him about halfway in on warmer nights. This makes it easier to zip him up all the way up in the middle of the night if the temps drop. Also, he has pretty intense doggy dreams, so if I don't zip him up part way, he tends to completely kick off all the coverings and then he gets cold. If it's really cold, he loves being zipped up all the way with 2 closed-cell pads.
I always make sure my pup is sleeping right next to me so I can monitor their temperature overnight.
Other things I have found that help when cold-weather camping with my dog, is to bring extra food, since dogs also need extra calories to stay warm. Also, as the days get shorter, putting a Ruffwear Safety Light on your dog's collar or a Nite Ize LED Necklace around their neck give them greater visibility if they wander off. I will also put a Bear Bell on my dog, not only to scare away animals, but also so I can hear them if they wander off.
Have so much fun with your adventure pups, and post pictures when you return! Here are some of my pictures!