I have some information regarding Victor Diffey b. 1805, including Death Certificate and census data. He may have been the father of your Owen b. 1833, because an Owen/Ewing is listed with him in the 1860 census and the approximate year of birth is 1832. Information I have regarding Victor's parents has been gathered from the IGI and other Diffey researchers.
I am happy to share what I have. Please email me on the address with this post, if you like.