I think there is a lot to be said for setting down all you know about a problem and then putting it aside for a while. Something may appear. It seems like you still haven't exhausted sources such as deeds and mortgages, also the Manorial Records.

You don;'t seem to know when the family lost tenure of Ballakerroo, and how the descent of that farm, and the Rhaa passed. Admittedly the mortgeges and deeds are a bit more difficult to access, but Lib Assed and Lib Vast are fully accessible on L.D.S. microfilms. As are the indexes to deeds and mortgages.