I love
Conall. I thought it was pronounced "KAWN-uhl" too, until I listened to a book on tape this weekend. The British narrator pronounced it "COE-nuhl." His Irish accent was pretty good, so I was persuaded. But if someone else has more informaiton, my mind is still open.
Conri looks insubstanial. It must be that "i" ending.
Sullivan would be OK, if it was from your own family tree. I like the nn Sully.