I believe that the Thomas Kiggins, who married Lydia Baxley was the eldest son of John Kiggins/Skiggins of Washington Co. PA & Brooke/Ohio Co. WV, and grandson of Fergis Kagan/Skiggan. Fergis also appears to be the father of the Jonathan, Robert, Thomas, and James Kiggins of Ohio and Texas.
I have spent a lot of time working under the belief that Jonathan, Robert, James, and Thomas Kiggins of PA, OH, & TX were the sons of James and Sophia Kiggins of Philadelphia. All the information did not fit as it should, and progress was limited due to an overall lack of new information. Brooke and Ohio County WV court records and histories show that the surname John Kiggins branch was using evolved/was synonymous with Skiggins (& similar varients). The name Skiggins is nearly unheard of, but can be found in the adjoining Washington County, PA (where Jonathan was supposedly from). Interestingly enough, it can be connected to a Thomas and James. This James Skiggins was about the same age as the James Kiggins who went to Texas, and both married women by the name of Mary Wolf in PA around 1800. The Skiggins/Skiggans/Kiggins group in Washington Co. PA/Ohio Co. VA appear to be sons of a Fergus Skiggan (1800 census), who I believe is the Fergus Kagan from Ireland, who ran from the ship after arriving in Philadelphia in 1765.