Well you now have the details of enlistment in 1855 which shows that he was already in the U.S. working as a cooper in Portland Maine...Fort Snelling would have positioned him at Hennepin Minn at one time or another...
Helen/Ellen Hanley says she was born May 1836 to 1840 Ireland..
There is an Ellen Hanly, servant born 1836 ireland, Saint Anthony, Hennepin, Minnesota in 1857
https://familysearch.org/pal:/MM9.3.1/TH-1-9835-31142-10?cc=1503055There was a sawmill near the St. Anthony Falls....just a thought, I tend to post what I find, these days, rather than have a pile of notes...
There are several Hanley from Ireland, in earlier census of Hennepin including a few in Saint Anthony
http://www.rootschat.com/links/019z6/I imagine you've tried to get some R.C. parish baptisms of their children if any exist?...Have you also written the parish to see if they have a marriage?