I agree with your assessment of the need for another wife for Joseph Adcock. Joseph Adcock was John Adcock's father, but Susan Cason cannot be his mother. Susan Cason must have been Joseph's second wife. I have a marriage date of 1777 for Joseph Adcock and Susan Cason given to me by George Adcock. I also have the same birth dates for the children. I have a different birth date for Susan Cason as 1750. Her father George Cason was born in 1730.
I appreciate the clarification on the birth dates of Joseph's and Susan's children. I too go through John Adcock 1754/56 with children Tenson, Edward, John, William (Billy), Patrick, Nancy and Samuel. I didn't know Samuel had a middle initial of C. Please clarify that this Samuel is married to Hulda Breazeale.
If I can be of any further assistance, please contact me.