Hennigan's Stead

Has anyone else noticed that on the agency's bodyguard laptop, there's an image which seems to show the swamps around Thieves Landing/ Hennigan's Stead?

I was experimenting if the Strange Man can be killed in the first game, so I went and talked to him, and then I shot him a couple times and did an execution kill, then he fell down a cliff. I lost honor by doing that, so I concluded that I must have killed him. He has not respawned and I am already in the West Elizabeth part of the game, so soon the mission cannot be doi. Is there a way to make him respawn so I can do the mission.