There was no John, Jr., but there was a nephew named John born in 1805. These Richardson men (at least two families) moved from NC to Georgia to Simpson County, MS and Louisiana and Jasper County, TX.
I know this much for certain. There were some Richardsons who traveled with my direct ancestors and lived with them in Simpson County, MS, St. Tammany Parish, LA, Jasper County, TX and Tyler County, TX. Same time periods, so it would be amazing if they were not inter-married at least once or twice. The LDS states Sarah Richardson (born 1800 or 1802) in Bulloch County, GA married Hilliard Durdin. She is one of these Richardsons, but more than likely a first cousin to the John Richardson you found. Cousin Brenda will sort it out. I am going to have a drink.