hallo
I have an Owen Rogan, born in Dundalk in 1872 in my tree; his son John Gerard Rogan married my great aunt Elizabeth Ryan. As far as I can tell, Owen's father was a Thomas Rogan, born 1825, but as you say, there are several Owen Rogans and I feel I may have mixed some up ( I was saving this part of my tree for a rainy day when I feel up to it!)
Tracey