Source: marriage entry in Coleraine Local Record Office - married in 2nd Dunboe, resident of Letterloan, full aged spinster, daughter of John McKeown. Daniel McKeown (along with Sarah Leighton) witnessed this marriage. This cannot be the Daniel McKeown born in 1878 because he would only have been 5 years old! This strongly suggests there was a Daniel McKeown in Rebekah's generation, and therefore another brother for my great great grandfather, James McKeown.
Middle name Anne from Emerald Ancestors using Civil Marriage (but they spell her name Rebecca).
N.B.: Placing Rebekah as the daughter of this John is speculative - Rebekah could also be the daughter of the younger John McKeown (son of John), except that the younger John's wife, Martha Dooey, was supposedly born in 1848, which makes her too young to be the mother of someone marrying (aged circa 20?) in 1883.