Tough finding records for this era and Young is such a common Irish name. Barbara was Palatine Irish. Her family moved from the Southwell estate in Limerick not long before her birth. Semple does not appear to be a Palatine name, but then Barbara did not marry a Palatine either.
If James and Mary married in County Kilkenny then that is likely where her family was located. Can't say for sure, but I'm not aware of any of Barbara's family that settled there.
Barbara's family brought their Lutheran faith from Germany with them. But by her time, the family had been converted by Wesley and were ardent Methodists. There is an old building on the Palatine road in Bawnlea which used to serve as the Methodist meeting house. It is now a cow barn on a family farm. The farm is owned by the Cooke's! I have pictures if you want to send me a private message, I can share them.