I think there is a marriage for John Ellis and Benneth Jones in Henllan, Denbighshire, of all places. It took place on 13/10/1838. She is named as Benneath Jones/Griffiths, daughter of John Griffiths, and he is named as John Ellis/Jones, son of Ellis Jones. An Ellis (Ellis), son of John Ellis and Gaynor, was baptised at Llanberis on 08/09/1816. I wonder if the elder John Ellis might have been a son of Ellis Griffith, the ancestor of Griffith Ellis ? I can find six baptisms for children of Ellis Griffith and Elizabeth Closs between 1783 and 1799, but none between 1788 and 1797. There seems to be a baptism for another son of John Ellis and gaynor in 1819, that of another son David.