Join the club I have hit a brick wall also. I have seen your family names in the Kilronan parish register but it is a long shot you are connected here. Leitrim is also another county you must try there is some mix up with boundaries last century and i have seen a reference to South Leitrim what ever this is.
Did any of these folk go to England or Scotland I found some of the sibblings through the LDS putting in marriages first only - and then births.
my background is that Thomas O'Rourke married Ann Keefe around 1840 I think in or near Boyle.
Their son James Rorke (b. 1844 Eire) married Mary Earley (Born 1845 in Keadew in the Kilronan Parish) in Edinubrgh parish in 1865. From this point onwards I know where the family are.Keep in touch. Good Luck ann