No spelling for O'Sh..... but plain Shaughnessy shows in the Griffith Valuations in Tipperary N.with 9 occupants.
There are 3x Michael, John, James, Edward, Lawrence and Bridget. His father's name will show in their children if not named after him its easier to spot. Usually 1st. son his father, 2nd. son her father.www.askaboutireland.ie
Spellings from the 1800's in Ireland can differ widely another reason that makes it hard to find people. Often the Irish dropped the 0' as they were no so easily identified as Irish when under the British occupation and put it back after leaving.
Good luck. Annette