K. J. Hanley:
Welcome to Ireland Reaching Out!
The RC parish records for Ballycastle do not start until 1864. I also checked the 1855/1856 Griffiths Valuation head of household listing for Doonfeeny civil parish which includes Ballycastle and there were no Rowan records listed. Perhaps Anthony and family had left for England.
Have you considered autosomal DNA testing?