Daniel Keogh

This fine looking gentleman is my great-great-grandfather Daniel Keogh. He had this photo taken at a studio on Regent Road in Salford. He was born in Ireland in 1829 and died in 1890 so the photo must have been taken sometime in the 1880s.
His son Matthew, my great-grandfather, was born in Manchester in 1866 by which time Daniel was about 38 years old.
His daughter Ellen was born in 1872 and from her baptism record we can see his wife was called Hannah.
Baptism: 13 Mar 1872 Sacred Trinity, Salford, Lancashire, England
Ellen Keogh - Child of Daniel Keogh & Hannah
Abode: Williamson Court Garden St
Occupation: Plasterer
Baptised by: J U Glanville
In the 1881 census he appears as a widower with his son Matthew and daughter Ellen boarding at the house of Hannah Birchall at 13 Croydon Street, Salford. Daniel is 52 years old and working as a plasterer. Matthew is 14, working as a cord machine minder and Ellen 9, is a scholar.
He died in Salford in 1890.
And that is all the information I can find about him, leaving lots of unanswered questions.
Where in Ireland was he born? Was Hannah his first wife? Did he marry her in Ireland?
Why can I not find census records before 1881? Why can I not find any other records? Or have I just got a lot more work to do?
The biggest enigma is how come Ellen was baptized at a Church of England church when they should have been Catholics.
Matthew Keogh married Ellen Nolan in 1886 at St Stephens Church, Hulme, Manchester which is also C. of E. They were the parents of my paternal grandmother all of them firmly belonging to the Catholic Church.
Ellen married John Manning in 1890 and had two children, Henry born 1891 and Daniel born 1893 before she died in 1894 at the age of 22.