Bob,
I researched this family for a lady some time ago to see if there was a connection with my mother who was born Margaret Keenan, in the event there wasn't but I seem to recall that Isaac Keenan was sometimes called Owen and Elizabeth, daughter of Owen Keenan and Catherine McCabe was born 27th November 1863 and baptised 25th December 1863 at St Joseph Catholic Church, Birtley sponsored by Thomas and Mary Coyle (I think Mary Coyle was a Keenan.) I will need to check my notes, but I believe that Catherine died about 1880 and Isaac remarried in 1885 and appears in the 1891 census as Kenny. By 1901 he was a widower again living with his brother John Keenan. I think the family originated fom near Newry, Co Armagh.
Good luck,
Mr Terence Arthur.