Repopulation isn't as slow as it used to. Look at Golden Farrow. Avernus stayed in the region for like a month and managed to increase its population by quite a lot. Usually regions stay depopulated due to monsters eating people and food. And yes... if you fight Astrum, you will most likely going to lose all peasants outside of Gelene Outskirt. But hey at least Hemmings will have fun watching his realm burn.
