The Sarah McIlha... is a mystery. She was the mother of the groom at a marriage on 17th August 1879 in Manhattan, New York. Her husband was Thos. Colgan and their son Wm. C. Colgan. He married Mary Hanson, daughter of Geo. Hanson and Ann Mooney. Presumably the last bit of Sarah's name was or became illegible. One possibility is that she was a McIlhagga born in the 1830s. I regret to say that I have no Sarahs on record from that decade. The second possibility is that she was Sarah McIlhargey, and I have seen a record of a Mary Sarah McIlhargey born on 31st January 1831 in Marysville, Ontario, Canada - at least on the 'right' side of the pond. She may well have been the Sarah born in 1831 to Archibald and Anne McIlhargey of Canada.
So I come to the McHaggars. FamilySearch contained two Williams, a Janet and a Lily. William and Janet McHaggar, father and daughter are certainly misspellings. This William was the eldest son of William and Agnes (nee McCosh). He married Elizabeth Carson, the mother named on the Scotland Births and Baptisms, 1564-1950, recording Janet's birth on 15th July 1862, in Greenock, Scotland. The second William's name is under Marriage for 1851 at Ballymena in the Ireland, Civil Registration Indexes, 1845-1958. Although no other information is given, I'm sure this William was son of David McElhager of Newtowncromelin, County Antrim, who married on 29th April 1851 at Ballymena Registrar's Office. He married Mary McGovern, born 1827. It is however the third and final McHaggar who is new to me. She is Lily, recorded as the mother of Chauncey Mitchell who was married on 22nd October 1913 in British Columbia, Canada. Chauncey was 25, so we can estimate a year of birth for his mother of about 1865. I have no further information about Lily, except that when her son was born they lived in Minneapolis.