kazz:
Hello again! Sorry for the delay in responding!
I searched the subscription site Roots Ireland and did not have any success with records for your family. I saw the 1754 baptismal record for Margaret Welsh in Tullow (surprisingly without a father's name). I did not find the marriage record but if the index for Tullow is correct, there is a large gap in marriage records from 1777-1799 (annotation shows only two records for 1777). https://registers.nli.ie/parishes/0735
I was also unsuccessful in finding any baptismal records for children of Michael Doyle and Mary Fitzgerald.
Let me know if you have any questions.
Roger McDonnell