The PRONI wills site has 3 probate abstracts relating to the Hayes family.
The Will of George Hayes late of Lecumpher in the County of Londonderry Farmer deceased who died 18 June 1861 at same place was proved at Londonderry by the oath of Henry M'Kee of Tuney in said County Farmer one of the Executors.
Above will is on-line and mentions sons Thomas (who inherited the farm), John, Hugh & Alexander (the last 2 residing in America), plus daughters Mary McKelvey, Margaret Stewart, Sarah Jane Ross and Eliza.
Letters of Administration of the personal estate of Eliza Hayes late of Lecumpher in the County of Londonderry Spinster deceased who died 30 October 1865 at same place were granted at Londonderry to Thomas Hayes of Lecumpher (Desertmartin) aforesaid Farmer the Brother and one of the next of kin of said deceased.
Above died intestate and so there's no will.
The Will of Thomas Hayes late of Lecumpher County Londonderry Farmer who died 5 January 1892 at same place was proved at Londonderry by William M'Geehan of Ballymacpherson in said County Farmer one of the Executors.
Above will is on-line and mentions his nephew Robert Hayes (who inherited the farm), and nieces Martha Bradley & Elizabeth Barclay.
Thomas was 66 when he died.
Robert Hayes in the 1901 census:
https://www.census.nationalarchives.ie/pages/1901/Londonderry/Brackaghs…
Note Robert was married. Is there perhaps some confusion between Thomas, who I think was single, and his nephew Robert who was married? Robert's wife was dead by 1911:
https://www.census.nationalarchives.ie/pages/1911/Londonderry/Brackagh_…
Roseanna Hayes (nee Latimer) death in 1908:
https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_retu…
George Hays in the 1831 census, at which time his family consisted of 5 males and 4 females, all "other Protestants" which may be Baptist in this case, since that was the denomination in the 1901 census. If so, you won't find any baptism records for the family, and that denomination does not baptise at birth.
Griffiths Valuation (1859) lists 2 Hayes farms in Lecumpher, beside each other. John Hayes had plot 13 which was 19 acres and George had plot 14 which was 21 acres. Both would be easy enough to locate today. They are either side of the A29 near Lecumpher Presbyterian church, just south from Desertmartin. The buildings on George's farm have all been demolished and it;s just farmland but John's looks to still be a large functioning farm, judging by a satellite image anyway. The Valuation Revision records (on the PRONI website) show both Lecumpher farms changing hands in 1912. A Henry Smith became the new owner.
Can't get any leads on Catherine Hayes.
