I have not read the other replies yet so you may already have my information. I am related to the Canavans and have some information.
Oral history has Patrick Canavan having two children.
He had Mathis Canavan and Simon Canavan.
I am from the Simon Canavan side but have information on the Mathis side. I just learned of Michael from realtives in Ireland. Up until then I only knew of five children. Micheal they tell is the sixth. So although I was sure we were conected I was not sure until now. The names you list, Canavan/Faherty/Mullen/ and Welsh, I have information about.
You can contact me at email@example.com