No record of a connection with James or Margaret Murray.
You're right - the family gad moved to Twyn Square by 1891, and then Church Street by 1901. I believe Ellen Murray (b. McCarthy 1829) died in 1898.
A Mary McCarthy aged 85 in 1881 would be a touch too old for mine, I think. She claimed to be 60 in 1861, and 73 in 1871 though, so she's heading in the right direction!
Mary did claim to be a widow on the census in 1861, so I think the Daniel connection is unlikely.
As you say, lots of families from Ireland all came over to this area at the same time.
I think they did it deliberately to make things awkward!
Theevath