James E. Smith & Mary Brady of Drung, Co. Cavan

I'm looking for anyone with knowledge of JAMES E. SMITH (born Co. Cavan circa 1825) and his wife MARY BRADY (also born circa 1825).  They married in Co. Cavan, but emigrated to NYC in 1855 on the "Drover" with two young sons, Patrick and John.  A daughter Catherine Smith was born after arriving in U.S.  Their names appear on an Emigrant Savings Bank record dated Nov 1866, showing James was working as a Gardener in Staten Island, NY.   At some point, James E. Smith disappeared. Mary (Brady) Smith and her children sought refuge on the farm of her paternal Uncle Patrick Brady of Websters Corner, Prince Edward Island (PEI), Canada.  Also living on PEI, was Patrick Brady's brother, Rev. James Brady (originally of Drung parish, Lappanbane townland, Co. Cavan).  Rev. James Brady had been assigned to the Ft. Augustus parish on PEI and had a devoted following (google his name).   

Note:  I am not blood related to either the Smith or Brady families.  My partner Steve Smyth (so spelled) is a direct descendant of James E. Smith and Mary Brady, through their son Patrick (who apparently changed the surname spelling to Smyth).