You may already have this information:

Peter Murphy = Ann Farrell 27 Oct 1839
St Francis Xavier R.C. Douglas, witnesses
James Collins & Catherine Rogers
children:
Elizabeth c.1841
Ann 10 April 1843 S.F.X. godparents James & Catherine Murphy
Mary A. 1846. She married John McGuiness 14 Jan 1864 ( I need to check this again)
Richard c.1849
Mary, 2 July 1856, godparents John & Margaret Farrell
Mary, 5 Sep 1858, godparents GeorgeMcKibbon & Mary Ellen Stowell
Peter 27 May 1860 godparents Richard Collins & Ann McGuiggan

Peter aged 20 years in 1881 census, plumber.

In the same house, 12 Market Street in 1881 were Peter's parents, Peter 60, gen lab. and Ann, 62, also his brother Richard & family.

Richard Murphy & his wife Mary Emma McNish had a large family
Catherine c.1871 born Manchester, England
Richard c.1873, Manchester
Christopher c. 1874, Manchester
Isabella c.1875, Manchester
Sophia, 27 Sep 1877, bapt. St Mary's, Douglas, godparents Thos. & Elizabeth Agnew
Peter, 13 Jan 1879, godparents William & Lucy Townsend
Edward 11 March 1881, godparents Peter Murphy & Elizabeth Agnew
Elizabeth, 13 April 1884, godparents John McKibbin & Ann Agnes Goodwin
Mary Emma, 14 April 1888, godparents Thomas & Catherine Agnew
George Edmund 23 Dec 1891, godparents Christopher & Isabella Murphy
John 11 Aug 1894, baptised in danger of death, godparent Sophia Murphy.

Marriages of children of Richard & Mary Emma:

Catherine Ann, 17 Market St. to James Barry son of Joseph, 10 Nov 1910, witnesses Christopher & Isabella Barry of 22 Market St.

Christopher, 16 Cattle Market St. to Isabella Sexton, dau of Thomas, 7 Quilliam's Court on 23 Nov 1895 witnesses Samuel Worthen & Catherine Ann Murphy

Sophia 16 Market St. to James Stewart son of James, witnesses William Townsend and Agnes McCartin (my paternal great aunt)

Elizabeth, Market St. to George Kneale son of George & Jane Mary Kneale, Hatfield Grove, witnesses Albert Gribbin & Mary Agnes Murphy, Thorn Hill, Shaw's Brow, Douglas

George Edmund to Esther Galbraith, dau of John 5 July 1912, witnesses Albert Gribbin & Mary Agnes Murphy

Richard Murphy & Mary Emma ( McNish) are buried in grave H39 Borough Cemetery. It appears they were buried on the same day 14 Oct 1927, Richard 78yrs, Mary Emma 76yrs, also in grave Margaret Gabriella 7 Aug 1926 (17yrs)

There are other records, but I have yet to link them with this family.

In 1891 census Richard & family are living at 25 Cattle Market St.

My paternal grandmother's parents (McCartin) are next door at 26

My paternal grandfather's parents (McCartan) are in next house 27 ( confusing having g.grandparents with the same surname but different spelling)

I'm sure we'll soon find a link with Murphy family living on the island now, whose children all attended St Mary's School.

Marie Radcliffe