The Internet site deceasedonline has added one McIlhagga record, for Robert, buried 1 Jan 1918 in Livingston Old Parish Kirkyard, West Lothian, Scotland. The authority supplying this information is called West Lothian Memorials. Apparently there is a headstone for Robert. The interesting question is this: which Robert is buried at Livingston? Could it be Robert Wright McIlhagga, who served in World War 1 and who died on 4 Sep 1917 and was buried at Rocquigney-Equancourt Road British Cemetery? Was his body brought to Scotland and reburied? This seems unlikely, though his name is on the Livingston War Memorial. Perhaps someone can enlighten us.
The second burial appears on findmypast.co.uk and is supplied by the Society of Australian Genealogists. It is for Lillian F. M. McIlhagga, who died 3 September 1957, aged 54. The inscription reads 'Our mother', in Rookwood Cemetery, Sydney, New South Wales. The grave is in Section J, Row 20. The Denomination is recorded as Independent. Interestingly this resource also tells you if anyone else is buried in the same grave. In this case there is one subsequent burial, that of Jean Marie Cormack, who died 22 February 1959, aged 25, wife of Colin Cormack. Jean Marie was in fact the daughter of Lillian.