Hi Sheila -- first, I would try the Archdiocese again and ask if there were any "Irish" churches in Louisville at the time of your ancestors' wedding. There were German churches for example, although there was prob. a larger German population.
Ask the Archdiocese also which churches were in the parish around their home that year. The 1900 census has a John Joyce/ Mary Joyce, on 8th Street. St. Boniface might be closest, but maybe there is another church that is closer.
Good luck --