Finish To the ends of the earth missions

[nidlo]

Hi

I'm trying to complete the stranger mission To the ends of the earth. I have marked the first, and third of these missions as done, but I can't start the other three parts. I look at an interactive RDR 2 map, and go to the locations, but there's no one there to start the missions through.

I've completed the story mode, so I should be able to start them.
What am I missing? I thought that maybe some of them are skipped, and tried the next part, but it can't be started either...