Lots of Aghadowey families went back and forth between here and Greenock (mainly to do with employment to at first then later also due to family members settling there). A man in Greenock, whose ancestors came from Aghadowey) that there were streets there with almost everyone from Aghadowey!
I can add another child to the list of children-
Maria Roxborough m.(1 Nov.1867 Garryduff Presbyterian Church) George Orr Shirley 23 June 1847-25 Apr.1935 Quincy, Mass.), son of Valentine Shirley & Nancy/Ann Orr. He m.2 (2 Jan.1879 Quincy, Mass.) Mary Moodie (1857 Quincy, Mass.-23 Dec.1933 Quincy, Mass.).
https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1867/11508/8232351.pdf“George arrived Dec.21, 1869.”
Passenger manifest list:
https://www.familysearch.org/ark:/61903/1:1:QK9Q-QYFX (Mary Shirley age 25, George Shirley age 20). Is this George & Maria?
1879 George's marriage to Mary Moody in Massachusetts list it as his second.
Boston Globe, 26 Apr.1935: SHIRLEY- In Quincy, April 25, George O. Shirley of 139 Quincy Street in his 88th year. Funeral services at the First Presbyterian Church on Saturday, April 27th.
I think Maria might have been a little bit older than George but he was only 20 (underage) so that might explain why they went all the way to Garryduff to get married. The minister was John Brown a nephew of Dr. John Brown of Aghadowey Presbyterian Church.
I haven't found any children born in Ireland, a death for Maria in Ireland or U.S. (George went to Penna. before settling in Massachusetts), etc.
If she is the Mary Shirley on the passenger manifest (1869) then she almost certainly died in America. In any case, she must have died before 1879. I have a full account of the Shirley family and George didn't have a sister called Mary.