Funny that a search on Lisnahunshin would turn up this very old thread. I'm actually investigating Henry O'Neill from Lisnahunshin as well--he was my 3rd great grandfather. From the marriage license of my 2nd great grandfather, Patrick O'Neill (b. about 1845), I know Henry was deceased in 1870. Not much beyond that.

I believe he had a second son, Joseph, who moved with Patrick to Coalisland, in County Tyrone. Anyway, it's a shot in the dark as Henry O'Neill is not an uncommon name, but...