Peter Maguire was born about 1878, possibly in Co. Tyrone, mother as yet unidentified and John Maguire, Labourer, who may still have been alive when Peter married in 1898.
There may be a service record in WO 363 - WW1 "Burnt Records" for Peter Maguire, Royal Inniskilling Fusiliers, service number 5594, born in 1878 in [allegedly] County Dublin. (access via FindMyPast - subscription or 10 credits)
But I still can't find a Civil Registration of the birth of a Peter or Patrick Maguire with father John in 1877-79 in either county.
Mary McCusker was born about 1879, possibly in Co. Fermanagh, mother as yet unidentified and Andrew McCusker, Farmer, who may still have been alive when Mary married in 1898.
In Civil Registrations, there are a fair few Mary McCuskers born 1875 - 1885, some in Fermanagh, but none with father Andrew.
1898 On Wednesday, November 2, Peter Maguire and Mary McCusker were married at the Roman Catholic Chapel, Enniskillen [St. Michael's] according to the Rites and Ceremonies of the Roman Catholic Church. The marriage was registered No.162 at Enniskillen in the Union of Enniskillen in the County of Fermanagh on the same day.
Peter was a Bachelor, of Full age, occupation Soldier and usual residence Derry. His father is recorded as John Maguire, Labourer.
Mary was a Spinster, also of Full age, occupation Farmer's Daughter and usual residence Enniskillen. Her father is recorded as Andrew McCusker, Farmer.
The celebrant was Thomas Duffy, C.C. and the witnesses were Patrick McBarrow and Mary McGowan.
The bride made "her X mark", all the others signed their names.
Peter and Mary had the following children (that I've heard of) —
Patrick John born in 1899, last sighting 1901. Robert James born in 1901, married Margaret Hann in 1926 in Glasgow
and probably died there in 1979.Leo born in Paul born in There are no likely births registered in Ireland for Leo or Paul 1901 - 1921.
1899 Patrick John Maguire was born on Monday, September 11 at Brackmount Terrace, Omagh to Mary Maguire formerly McCusker and Patrick John [sic] Maguire, Corpl. in Army. His birth was registered No.299 at Omagh in the Union of Omagh in the County of Tyrone on September 29 by P.J. Maguire, Father.
1901 Robert James Maguire was born on Thursday, February 7 at Gortmore, Omagh to Mary Maguire formerly McCusker and Peter Maguire, Sergeant in Army. His birth was registered No.166 at Omagh in the Union of Omagh in the County of Tyrone on March 18 by P. Maguire, Father.
1901 March 31 The family were living in the Military Barracks in Gortmore, Omagh Town, Co. Tyrone, where they had 2 rooms.
Name Rel. Religion Educn. Age Occupation Mar. Where Born Peter Maguire Rom.Cath. R & W 23 Lance Sergeant Mar Tyrone Mary Maguire Wife Rom.Cath. R & W 22 Mar Fermanagh Patrick John Maguire Son Rom.Cath. 1½ Unm Tyrone Robert James Maguire Son Rom.Cath. 1/12 do. Tyrone Susan McCusker Visitor Rom.Cath. R & W 19 do. Fermanagh [St. Lucia Barracks, [Gortmore,] Omagh was a base for the 1st Battalion, Royal Inniskilling Fusiliers, formerly the 27th Regiment of Foot.]
[Susan is not the Susan McCusker born in 1884 to Anne & Redmond McCusker of Ballydoolagh who is at home with the rest of her family.]
1911 I can't find any reasonable Peter, Partick or Robert in this census, anywhere in Ireland.
1926 On Thursday, September 2, Robert married Margaret Hann at St. Mary's, Abercromby Street, Glasgow. [See Section MA-7-1 for further information.