The marriage record has additional information that suggests how Mary "Polly" Wainscott was related to Catherine, Richard, and John C Wainscott--as well as to Drusilla Wainscott who married John McGibney,
The parental consent and the witnesses statement say:
"Consent of parent is given: We do certify that we have given our consents for a marriage between my daughter, and my sister, Mary Winscot, and Daniel Lett, the clerk or deputy clerk of Owen county court is hereby authorized and requested to issue a license accordingly. Given under our hands and seals this 11th day of February 1824 . Catherin Winscot (seal), Richard Winscot (guardian). Witnesses by John C Winscot & John McGibney"
This document names Catherine Wainscott as the mother of the bride Mary Richard Wainscott as the brother of the bride Mary and John C Wainscott and John McGibney appear as witnesses.
If I'm not mistaken, John C Wainscott was a brother to Richard (and so a brother to Mary) and John McGibneymarried Drusilla Wainscott on 15 Jun, 1820 in Owen co KY, making him a brother-in-law to the Wainscott children and son-in-law to Catherine (if indeed she was the widow of John C Wainscott, jr).
If I have generations of the Wainscott family with the same names confused, I would certainly appreciate learning more about the family.