Orr family from Ballymacward, Derryaghy, County Antrim, Ireland

Friends!!  I've been searching for years to try to find my GG Grandmother, Margaret Orr's origin. The 1861 census for Toronto, Ontario showed Margaret was born at County Antrim. A relative has Margaret's sampler she made at 10 years of age in 1833 in Ireland, and from other info I suspect she was born about December 7, 1822, but can't be absolutely sure of the date. My Margaret Orr was working as a servant at Downpatrick when she married my GG Grandfather, John McMullan, a shoemaker at C of I Downpatrick Cathedral May 2, 1844. With DNA, I discovered Margaret's younger sister, Anna Orr, may have been born about 1826. Ann Orr and spouse, Thomas Haveron/Havron were at Low, Quebec after they emigrated to Canada. Margaret was married at least 4 times, and two marriages show her parents as David Orr and Catherine (unknown maiden name). A shared DNA match has an Orr line from Derryaghy, County Antrim, Ireland, who I believe have a John Orr, about the age David Orr might be, so they could be siblings?  I found 1829 and 1831 news articles showing some Orr's had land at Ballymacward, Derryaghy, County Antrim, Ireland including a David Orr, who I suspect was my ancestor. I have a number of DNA matches that I believe work back to the area of or near Derryaghy which might be for a spouse of an Orr. I can't be sure of the surname, but two possible surnames of a spouse might be Scott or Johnston?  On the 1852 census, Margaret and two sons were staying at Montreal with an Irish William A Johnston family. I don't know if they were related, but possible? Margaret married at C of I; had son who died less than a year later at an Anglican Church at Quebec City; but from 1852 on she was Wesleyan Methodist or Methodist. I don't know if records might exist for a Parish in the area of Ballymacward, that might show a marriage for David Orr and a Catherine, births for Margaret and/or Anna, or other siblings; and/or perhaps deaths for a David and/or Catherine Orr. I've suspected Margaret's parents may have died prior to her marriage in 1844, but??  In 1844 Margaret was working as a servant, perhaps for a relative at Downpatrick? I would love to learn more about Orr lines of the area, and any information I can glean about David Orr and Catherine!! My research ability has slowed as I am legally blind, but can see some online, so do what I can. Margaret was married 4 times and perhaps more, and unknown? Margaret died at the Wellington County Ontario, House of Industry (poor house) in 1910 with memory issues. I've never found the fate of first husband, John McMullan after 1852. He either died in Canada or perhaps left the family? So far, I haven't found a death I've thought might be him, and I've reached out to those who have records for the areas I believe he lived in Canada.  Thanks so much!!  Tom McMillan (State of Washington, USA)