I just realized something. John and Abigail have already had Jack at the point in time when RDR2 is set, 1899. Jack Marston was born in 1895, so he'd be 4 years old when this game takes place. We also know that John and Abigail had a daughter at some point before he left Dutch's gang in 1906, a daughter who later died, so we may see John's daughter as well. Will really be interesting to see what it was like for John and Abigail to try and raise kids while they were outlaws on the run.