I have no advice on the sleeping bag, but I can attest that two dogs in cold weather camping are very helpful. The last time my husband and I took our two dogs camping, we figured we'd get one dog each to keep warm. Instead, both dogs chose me -- one on my legs and the other on my neck.* My husband froze his ass off while I stayed toasty warm.
*
Our dogs weigh 40 and 50 lbs, which means that while I was warm I also could not move the entire night.