I have a "lost" Allen who I believe might be a brother to John Allen Jr.
Thomas Allen, born abt 1750, not sure what county in NC. Census and tax records indicate as an adult liing in Surry Co., NC. He was a Revolutionary War vet and was granted land on North Hunting Creek, Surry Co., 1779.
He married Wineford/Winifred Armour 1778, Pasquotank Co., NC. Not sure if he is from that area -- the Armours were, though. I found in the 1754 North Carolina Census a Elizabeth Allen as head of household, then in 1769 a Benjamin Allen in both the tax list and the census.
I'm trying to find Thomas' family. His known children are named James, Richard, Thomas and William, but they are common names for the day.
Richard his son is my ancestor, and he had many children as he was married 3 times: 1805, Surry Co. to Sarah "Sally" Johnson; 1832, Wayne Co., IN to Betsey Foster (who died the next year in childbirth); and lastly to Elizabeth Wood around 1834/1835, we believe in NC (he made a return trip for business, met Elizabeth, married, and brought her back to Indiana, where in about 1836 she had her first child, Richard).
Richard's children were Levi, Elizabeth, Letitia "Lettie", Jesse (my ancestor), Harrison, Washington, James, Reuben, Mary, Richard, Thomas, John Jane and William.
Just writing to see if any of this may fit into your family's scenerio.