Eileen:
I searched on the subscription site Roots Ireland and located a February 25 1819 marriage between a Richard Shea and a Mary Connolly. The marriage was held in the Kilmacow RC parish which is just to the west of Slieverue RC parish. Both parishes are in the very southern part of Co. Kilkenny. Both the bride and groom were shown as living in a place called Smartcastle which has to have been a local placename. They must have moved east to Drumdowney while Mary was pregnant and Margaret was baptized on December 19 1819.
By the way, I did not find a good lead on a John Shea that was a child of Richard and Mary.
Drumdowney is in the civil parish of Rathpatrick and the 1850 Griffiths Valuation head of household listing for that civil parish shows Richard Shea in Drumdowney Upper townland and there was also a Patrick Shea in that townland. I don't believe this Patrick was his son but likely a brother, father, uncle etc.
Civil registration of deaths started in Ireland in 1864. The free site www.irishgenealogy.ie has index records for deaths between 1864-1870 and the actual death record images from 1871-1970. I looked for a Richard Shea record and found a record in 1873 for a Richard She who was 82 and lived in Ballymountain townland which is in Dunkitt civil parish which borders Rathpatrickparish. Richard was a widower and the informant was a Mary Shea who was not his wife. Could have been a relative.
see seventh record https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_retu…
I did not find a good lead for a death record for Mary Connolly Shea.
The 1901 census for Ballymountain had a Walter Shea (age 45) family. Not sure how he is connected to Richard but he is too young for the Walter born in 1829.
http://www.census.nationalarchives.ie/pages/1901/Kilkenny/Dunkitt/Bally…
Have you tested your DNA? If you have not, you may want to consider a test. You may get matches that will assist with your family research.
Roger McDonnell