My Mary (Fagan) Mulligan was married to Edward in 1859 in Coole, RC parish Mayne in Westmeath. So we are, sadly, not interested in the same person. Although I speculate they had a daughter Mary born between 1860-64 who immigrated to NYC and married Samuel Kerwan. The Mayne church records are missing for those years so it has not yet been confirmed except that the parents were in Oldcastle Meath in the 1901 and 1911 census where they state they have 9 living children, Mayne church records do have 7 births from 1864 to 1878. Mary and Samuel had a daughter Margaret who did not marry. Also living with them was Mary's brother Edward Mulligan who is about the same age as the Edward child in the Mayne records. My mother and her parents lived next door to them in the 1920 NYC- Queens census.
The children of Mary and Edward baptized at Coole include Peter (1864), Edward (1867), Julia- my grandmother- (1869), Catherine (1871), John (1874), Daniel (1876), Bartholemew (1878). Catherine and 'Bartle' were with the parents in the 1901 census, Bartle still with them in 1911. A possibility is that Catherine is the 'Katie' Mulligan who married in Oldcastle in 1903.