Welcome to Ireland Reaching Out!
As you indicated there are over ten William Flynn baptismal records around 1844. I looked for a record in Imogeela parish with no success. I then checked Midleton and found an 1842 record. No idea if this is the correct record. Did they have children and if so, what was the name of the oldest son?
You may also want to consider autosomal DNA testing.
Name:William FlynnDate of Birth:
Date of Baptism:15-Jun-1842Address:MidletonParish/District:MIDLETONGender:MaleCountyCo. Cork
Father:Denis FlynnMother:Bridget CashmanOccupation:
Sponsor 1 /
Informant 1:James DalySponsor 2 /
Informant 2:Margaret Walsh