The second interesting thing about this family from a genealogical perspective is that we have an example in it of a distinctive name, William Gage McIlhaggo/a - one of the brothers who married Mary Houston. And there is a second 'William G', son of the brother John, though at present I have no firm evidence that the 'G' stands for Gage. I assume that the name Gage was the maiden name of a clan wife, perhaps a couple of generations back, or even the name of a maternal grandmother.
Now some time ago (in 2003) I had a letter from a lady who told me her father was a William Gage McIlhagga born in 1904, and was I think wondering where the name came from. He had been married to Mary Bishop and was one of the nine children of another William Gage McIlhagga (1865-1930) who married Jane Todd in 1890. This William was a shipwright who worked on the building of the Titanic at the Harland and Wolfe Shipyard in Belfast. He was one of twelve children of John McIlhagga (1830-1912) who married Elizabeth McCulloch. We know from their marriage record that John's father was Henry who must have been born about 1805-10. The frustrating thing is that we have here two families in which the distinctive name of 'Gage' occurs at least twice, though we have no certain link between the two families. It is however reasonable for us to think that the two families must be linked, and to speculate where the link might be. What we can say tentatively is that Henry the father of John was clearly of the same generation as the brothers John and William Gage. If all three were in fact brothers, then they were all sons of Henry and Mary McDole/McDowell and possibly all grandsons of a female Gage who had married Henry's father. Unfortunately at present we do not know the name of the mother of John (who married Elizabeth McCulloch), nor of the father of Henry.
To complete the picture of the second family as we have it at present, we can list the siblings of each of the William Gages. The siblings of William Gage who married Jane Todd were Mary born 29 June 1860, died 14th October 1940; Samuel McCulloch born 19th November 1861 who married Agnes Nisbett and had a son John, and died 11th January 1920; Elizabeth born 17th May 1863 who married Patrick William Orr and died 5th February 1952; [William Gage]; Agnes born 20th March 1867; John born 28th September 1868 who married Esther Loakman and had six children and died 18th September 1868; Robert born 8th June 1870 and died 13th April 1951; Jane born 17th February 1872; Rebecca born 18th July 1873 who married Charles Kennett; Wilson born 18th April 1875; Henry born 10th June 1879 and Sarah born 1882. The siblings of William Gage who married Mary Bishop were Lily/Matilda born 1891 and who married Robert H. Rush on 13th July 1914 in Crumlin Road Presbyterian Church, Shankill; Agnes Ethel born 1892 and who married William McVittie on 27th October 1915 in Crumlin Road Presbyterian Church, Shankill; John born 12th September 1893 who probably died before 1900; James Wilson born 1894; Lucy born 7th August 1895; Sarah Jane born 1897, John born 1900, [William Gage born 1904] and Robert born 1905/6.