Hi Dallas.
I would suggest a DNA test from a male Kelly relation. It's the only way forward when vital records are missing. I spent 15 years up and down cul de sacs, climbing high walls, crossing deep ditches etc, and it was not till I did a DNA test that I was able to get on to the right track.
There were about 7 Kelly clans in Ireland and DNA will tell you which particular Ó Kelly sept you are from, then you can focus and hopefully get on the trail.
Best of luck,
Joe Kelly
Dublin
Ireland.