Hi COConnor,
I just ran across this post today. I think we might be related. My great-great grandfather, Michael O'Connor, was also from County Cork, and is believed to be from to be from Ballydineen, Doneraile Parish. We know he was from "near" Mallow. (Doneraile is certainly near Mallow.) In the 1990s my parents researched him and found records of a Michael Conners born (or baptized) on 19 Nov 1820. This Michael Connors was from Ballydineen, Doneraile Parish. His father was Timothy Connors. Interestingly, Griffiths Valuations for Ballydineen for 1833 shows a John Conners and Timothy Conners as holding land. (This site isn't allowing to post the link, but you'll find it if you Google Ballydineen Doneraile tithe appointment books.) They're clearly related (although I'm not sure how) since one parcel is in both names (the other parcel is just in John's name). I suspect that John and Timothy were brothers.
Michael O'Connor definitely immigrated to Philadelphia, as most of his children were born there, including my great grandfather, James Joseph (J.J.) O'Connor, were born there. The family later moved to San Francisco in 1858 or 1859 (he had a child born in San Francisco in December 1858 and is found in the 1860 Census on S.F.). However, it is believed that he emigrated from Ireland during the Famine, not as early as 1841. I believe that family tradition stated that he emigrated with a brother or cousin, although I couldn't swear to that. So, we may be distant cousins.
My family has tracked virtually all the descendants of Michael O'Connor but none of his ancestors or their descendants except for the above-mentioned Timothy Connors. Have you submitted DNA to ancestry.com or 23 and me? (I've submitted on ancestry.com. My daughter Brenda had submitted on 23 and me.) It would help both of us piece together and confirm our family histories if we show a match. Have you discovered any additional information since you posted?