Thank you for trying ! Another researcher who is a descended from James ALEXANDER who d. 1753 and I have been working together for the last year on our two families. As you pointed out, the given names in the two families are quite similar - more so than in any other extended Alexander family. We have not yet found a connection.
Of course, James who d. 1753 was in North Carolina several decades before my family who arrived there in 1778. But there is a possibility that the father of my James Alexander (1749-1825) and his brother, John (1740-1800), was a brother to James who d. 1753. We are working on that angle.