I've got 3 day respawn running. The Enclave solder that hangs around the water tower in front of Wasteland Motors, followed me in there and I klled him. I have in the past been surprised that they came in. Being caught off guard he was alble to Kill Fermando, which would svck. In the previous instance I just reloaded and then didn't try to run away into the building and stayed outside and fought.
This time however, a solder followed me in tehre and and I killed him. Now I can't get his body back outside and I expect when he respawns he'll kill Fermando?