Interesting thread. I was an Eagle Scout and spent many a winter night remote camping. I always had a goose down mummy bag and a Therm-a-Rest pad and had a good dinner of hot soup before I retired.
To this day, I believe in a good down bag. I still carry one in the camper. My bag now is a Kuiu mummy good for 5 above.
I would have suggested feeding them all pork and beans for dinner and group sleeping under flannel blankets with plastic film under the tents.
Those beans would have produced the necessary heat under the blankets to keep the kids toasty all night.....