I say let hubby be hot than. Baby comes first
A heating pad should not be needed. How cool is "pretty cool"? I would give blankets in puppy's sleeping area and put a sweater/clothes on if they appear cold.
I never use the central air. I will use a small wall unit when I am sleeping in my room but otherwise no. Roxy and Zoey hate to be cold so they always wear clothes unless it is super hot or bury themselves under blankets.
It is recommended pups stay with mom til 12 weeks by the YTCA.