referring back to the townland mentioned earlier i.e. Slievenagrane, it's in the Civil parish of Castle-Ellis, which was one of those included in the RC parish of The Ballagh/Oolart.
No sign of any [O']Byrnes or [O']Neills in the townland at the time of Griffith's valuation in 1853, which may have helped follow the family forward. Maybe the family later moved from the area ?