Sean,
I have very little information on the Jemphrey family beyond the estimated birth years of the seven children, with the exception of one son - Robert Jemphrey. According to the census available online, they lived in Belfast at one point in the Duncairn Ward before moving to Bessbrook (House 19).
Robert moved to New Bedford, Massachusetts. I cannot give you exact dates, but my estimation from postcards is that it was sometime around the early 1910s. He married Mary R Carlaw (1882-1956). Unfortunately, he died during his WWI service in 1918. There is one daughter from this marriage, Grace Jemphrey (Later Hallett) who was born on 02/20/1919.
I'm not sure how much you want of this line of ancestry as I can continue until the generations from present day, but I cannot say what happened to the other sons. Due to the fact that this is recent information I have found, I still haven't used all of my resources to find out more about the family. I do have postcards (and photographs? - no one is identified in the photos, so they are not of use) sent to Robert, but I don't see anything of importance beyond numerous Bessbrook themed postcards.
I haven't looked up the dates of death for the other brothers, but this is what I have:
David Samuel - 1886
Thos Herbert - 1887/1888
Robert ("Bob") - 1890-1918
Alfred - 1892
James - 1894
William Edward - 1899
Richard Jemphrey - 1902
I do have a confusing postcard, though, that states an "Etta" as being Mrs. Robert Jemphrey - so I am unsure about this and will have to look into this further.
Hope this helped you out on what you were looking for.