Kirchenbuch for St. Peter's Reformed Lutheran Church in Tuscarawas Co, Ohio, translated and transcribed by Maxine Renner Eberle - 1981, in the library of the Tuscarawas County Genealogical Society, lists on p. 55, the marriage of Christian Denzer and Margaretha Feigert, 19 Jan 1854. This marriage is also in an IGI entry, batch 7916501, sheet 95, microfilm 1260554. I'm not actually sure it is the same Margaret Figart who is Frederick's daughter, but am assuming so on the basis that she was the only single Margaret Figert/Figart in Tuscarawas County in the 1850 census who would be of marriageable age (Peter's daughter would only be 11 in 1854.) Also, the marriage was in the same church as that of Frederick's son Jacob.
Another volume of this Kirchenbuch, transcribed 1982, lists on page 8, "Christian Denzer and his wife Margaretha nee Feigert, as the sponsors at the baptism on 20 May 1855 of Margaretha Deibel, daughter of Peter Deibel and Elisabeth nee Wolf. This is the latest mention of the couple in Tuscarawas County Lutheran church records.