Read the About of James Cantrell's father. James' mother was the second wife, Elizabeth.
Note that many of Tabitha's children named a child after her, which James did not. In fact he named a daughter Elizabeth.
I would go to the source cited on the About of Isaac Cantrell and check, but the About makes it fairly clear. It is clear that a child born in 1769 was Elizabeth's daughter.
It's common that with the first child or children born to a second wife, after the first wife died, there is some confusion or disagreement as to the parent.
Here is the pertinent part of the About:
Isaac's will left all his land to his wife for her lifetime, but the court concluded that the will was valid for the personal property, but not for the land. Peter Cantrell, Isaac's son by Elizabeth, brought an action in the Court of Common Pleas of Spartanburg County in October 1807, suggesting that one third of the land be given to the widow, Mary Cantrell, as her dower, and that the rest be divided among the 19 heirs of Isaac Cantrell. The widow had no objections, and she was assigned 200 acres, including the plantation house. The remaining land was to be sold and divided among the heirs. However, this was not likely to enrich the heirs, as the entire 862 acres was appraised at $650.50, less than $1 per acre. By the time it was divided among the 19 heirs, probably no one got more than $25. Why only 19 heirs were listed is not clear. Apparently, two of Mary Linder's children had died young, which left 23 heirs. One of Talitha's children also apparently died without heirs, but two of Talitha's children were omitted from the list of heirs: Mary Cantrell who married Sampson Bethel, and Elizabeth Cantrell who married her cousin John 'Miller John' Cantrell. James Cantrell, son of the second wife Elizabeth, was also omitted. Possibly these chose not to join in the court action; they may have been given some property by their father Isaac at an earlier time, with the understanding that it would be their share of his estate. At any rate, the list of 19 heirs has been very helpful in establishing who the children of Isaac Cantrell were. The following list of his children may not be totally accurate, but it is a much more comprehensive list than was available when the 1908 Cantrell Genealogy was written. ( byThomas G. Webb)
http://dmitchelljones.org/can3.htm
