To start with this thread should be on the ANTRIM board with other Belfast queries but not sure if 'report to moderator' function is working at the moment.
Gerry- could you provide dates for the people buried in the plot you mentions (and where it is)?
Here's Terence Devlin and family in 1911-
https://www.census.nationalarchives.ie/pages/1911/Antrim/Smithfield/Falls_Road/186904/He and son Patrick born Co. Tyrone but daughter Mary born Co.Antrim. Terence and wife Mary only married 6 years.
Son John's birth registration gives mother as Minnie (a nickname for Mary) Kirk.
https://www.irishgenealogy.ie/files/civil/birth_returns/births_1910/01575/1634654.pdfMarriage of his parents in 1905 gives Terence's father as Patrick Devlin (dead).
https://www.irishgenealogy.ie/files/civil/marriage_returns/marriages_1905/10161/5697000.pdfTerence, wife Maggie and children in 1901-
https://www.census.nationalarchives.ie/pages/1901/Antrim/Smithfield/Falls_Road/952802/In this census Terence, wife Maggie and son Patrick born Cookstown, Co. Tyrone.