Thank you very much for your query to Ireland Reaching Out. How do you know they are from County Cork? Where did you find the information you have? Have you spoken to other family members about your ancestors? If not, please do, because sometimes family information and stories are known by some members and not others.
When searching records, please check all other spelling variants of the name Keefe, such as Keeffe, or O'Keefe, or O'Keeffe, etc.
If you find a more precise location for John's origins, then you'll be on a roll. This should be your main focus now. Where did you find out about Daniel? Did it offer any additional clues about John and Margaret?
Please keep in touch, and best of luck in your research!