My recent searching has led me to believe that the Tribbey etc. branch that came as Quakers from Wales actually were known as Tibbey or Tibby in Wales. I did find some evidence that the orginal name was de Tibbay or something similar.
I have come close to being able to say that the original Tibbey in the Welsh Tract in PA. was a John Tibbey. Legal records show he was on a jury in Jan. 1682. William Penn arrived on the "Welcome" in Oct. 1682. This Tibbey bought 250 acres in Buck County, PA. He arrived with his son Thomas when Thomas was still very young. John's wife was Elizabeth, not to be confused with the Elizabeth Fabian that his grandson, also John,married.