I have Patrick McShane's wife's last name as Densmore. I am pretty sure that I would have gotten that information from Shirley O'Neill. Patrick's son James married an O'Neill, of which I am one.
I know no other information than that, although I believe you may find that information in the microfilm St. Andrews NB Catholic Records to 1900 found in the St. Croix Public Library in St. Stephen, or at the archives in St. Andrews. Sometimes when someone was a sponsor at a baptism they would give the maiden name of the wife.