when we made the breakfast in a bag, the fire was just hot coals. We had made little cookers out of 3lb coffee cans for this.

Put several strips of bacon in the bottom of a paper lunch bag then shake an egg up, break it open then drop it over the bacon. Put that over the coals and let it cook. The bacon grease burns at a higher temperature than the bag, that helps to keep it from burning up. Actually works well.