As long as everyone is dead, just consider it a job well done, and don't worry about having a neat quest log.
But then there is no exp if the quest is not done is there?
Hunter's Edge is really a weird place, I had also another problem (also bug?) there in the wizard house. I found the prisoners, freed them then I found the others in their hiding place. I also managed to deactivate every trap in the house of the wizard, then deactivate every door and was able to use the portals. My logs say I should contact the people that the house is safe - but nobody of them is reacting/there is no option to tell them that.