I strongly suspect Mary and George do not belong in the family of Laughlin & Elizabeth. They may instead be grandchildren, or more likely, a nephew and niece. There are simply too many Flynns of similar name and too much faulty earlier research. Mary & George were apparently still in North Carolina and married in North Carolina, although Laughlin Flynn had already gone to Kentucky while they were in their teens.
Mary named no son Laughlin, but she did name a son Hezekiah [a name from the Wright family] and she named a daughter, Delpha. The only Delpha Flynn was the daughter of Thomas Wright Flynn, who was most likely the son of Thomas Flynn & Sarah Wright. Thomas believed to be brother of Laughlin; Sarah Wright a sister to Laughlin's wife Elizabeth. Proof for all these connections is scant to say the least and more research is needed.
Evelyn Hall says the marriage took place in Stokes Co NC - the bond definitely says Surry.
Polly & Alexander also moved to Greene Co IN about 1830. Alexander died sometime after 1880.
1860 Census. Taylor Twp, Greene Co IN, Hh 1270
Hezekiah next door in Hh 1271
1870 Census. Taylor Twp, Scotland P.O., Greene Co IN, Hh 26
Mary "Polly" FLYNN and Alexander JOHNSON had the following children: