Of course, the James ALEXANDER that you have mentioned in Rowan County in 1750s would not be the same man that I was talking about who was b. 3 Jan 1790 in Lincoln County, North Carolina. So far as I know at this time, there is no relationship between the two families.
The James ALEXANDER that you mentioned who died in 1753 could not be the one who lived in Salisbury in 1755. Actually this older James is fairly well documented in court records subsequent to his death at the time of the dispersal of his estate. His oldest son was William and his other sons were James, John, David and Robert. His daughter was Eleanor and his wife was Ann.