Hi cousin! I am related to your Irena's side of the family. If you don't already have this, I hope this is helpful!
Irena's parents were Israel Willcockson and Mary "Polly" Fleming, married Dec. 2, 1809, in Clark Co., KY, officiated by Rev. Edward Kindred. Israel died in Boone Co., MO, and Mary "Polly" who went with some of her children to Iowa, died March 17, 1873, buried in Dooley Cemetery, Davis Co., IA. (Find a Grave)
Israel was a son of John Willcockson, Jr. and Sarah Notson. John Jr. was a son of John Willcockson, Sr. and Sarah Boone, sister of the famous pioneer, Col. Daniel Boone.
The following are Will abstracts which hopefully provide a few more clues for your search.
Wills & Adm. of Boone Co., MO 1821-1870, compiled & published by Mrs. E. E. Evans, genealogist, & Mrs. J. F. Thompson, genealogist, Columbia, MO, copyright 1932, by Evans and Thompson, reprinted 1992 by Genealogical Society of Central Missouri:
p. 72: “Joseph Sloan No. 1728: Adm. Joseph F. Sloan, Admr. Gr. Apr. 20, 1860, Heirs – Irena Sloan, wid.; Amanda, Mary, Malisia, Delilia, Ellis, Margaret, Jacob & Joseph F. Sloan of Boone Co., MO, James Sloan of California State."
p. 89: “Irena Sloan No. 2098: Adm. Wm G. Windsor, Admr. Gr. Sept. 26, 1865.Heirs – Mary E. Payne w. George W. Payne; Malissa Sloan, Susan E. Sloan, Sarah A. Sloan, all of Mo.; Jacob E. Sloan, Margaret Sloan, Leonia Sloan, Joseph F. Sloan, reside in Iowa; James Sloan who resides in California.”