You might be able to find her birth record onwww.emeraldancestors.com
an Irish History Foundation, there aren't too many records but think you have a better chance with 1830's.
I looked in the Armagh Directories for Charles Murphy and there was 1 listed in Newry, Armagh for 1881. I went over the page 3 times and I just can't find it.
I looked in the Griffith Valuation of 1863 for Armagh, several Charles Murphy's with land and house/houses so more than 1 of them. Nothing to indicate he might be an architect but I think someone who was would likely be better off than a farmer and might have several pieces of land. www.askaboutireland.ie
McCausland, quite a few but in the 1881 Directory for Armagh
Manager Robert McCausland, Gilford, Armagh also would be better off than a farmer and might be social equals?
As this is Northern Ireland you will need the british telephone book to look up and see if there are McCausland
in Armagh. The name Murphy is the most common name in Ireland. There are 3 McCausland listed in Dungannon, Armagh and at least 10 pages of Murphy's.www.censusfinder.com
She left Ireland at the end of the worst famine in their history. I don't think it would of been a good place to be
unless you were well off. The poor starved to death.