Alexander's will proves that he died in Northumberland County VA in 1727. I haven't found a single Ancestry, MyHeritage, or other tree that contains supporting sources for the first name John. Nor is there a record of his death or burial in Onslow NC. The Find-a-Grave memorial with the 1773 death date has no supporting sources and no gravestone images, so must be discounted.
Alexander's will is the best source for his life information. It names just wo sons, Amos and William, and one daughter, Elizabeth. It also names four youngest daughters, presumably minors. There is no Hannah, no John, no Alex, no Jane, and no Judith. So far there are no sources, besides unsourced trees, attaching any of those to this or any other Alexander.
