William,
If you visit this web site, you can find out a good deal of information about Andrew Sexton. The authors of this website can tell you a good deal more about Andrew and his family.
http://freepages.genealogy.rootsweb.com/~morrgary/families/s...
Jerry Jordan listed in the credits has written a book that includes letters written by Andrew Sexton to his sister Catherine Sexton Jordan. One of Andrew's letters was written shortly after the death of his first wife. Contact me at my e-mail address or one of the authors of the site and we can tell you how to get a copy of the book.
Ian Brown who has postings on this message board is a more direct descendant of Andrew than I am. Just type his name in the search at the top of the page.
Margaret C. Sexton was Margaret Catherine. I would assume she was named after Andrew's sister Catherine. The sister you have listed as Tabitha was Telitha Cuma. (Apparently, it is a Biblical name.)
We don't have a record of Margaret's second marriage, so that would be nice to add to the information. I do know that Estes is not an uncommon name in that part of southern Illinois.
Would you like me to send you pictures of Andrew and Mary number 2's gravestones?
Kathy