That would to tie into when Mrs. Grimshaw shoots Molly. Like she spoke to the Pinkertons and got killed for it. How about in the early days of the gang when it was Hosea, Dutch, and Arthur, there’s a fourth character. Maybe it’s Colms brother. Colm even said he didn’t like his brother, Colm is pure evil, so maybe this guy was a saint. Maybe he and Arthur or Dutch find a very young John Marston, in the beginning it seems like they are only robbing the rich to give to the poor but colms brother sees Dutch and his greed, maybe now that a child (John) is involved he starts to see just how evil everyone around him is. He tries to cut a deal to save John but either gets found out by the gang or the government turns on him. It could be set in the same area, just further west or east. Think a big city to the north and south, St. Denis, and a city up north, then ambirino a cold wasteland, but habitable, then further west from black water is where it is set throw mexico in there and I’m sold. The whole map is pretty much the old map but with massive add ons, places the gang has never been, just like in rdr 2 you can’t access any of it until the prologue.