We may have a connection. My grandfather James Fitzgerald was born in Castleisland, Kerry. His father was James Fitzgerald, his mother Mary Lyne. I couldn't find a James Fitzgerald Christening in Castleisland with James as father and Mary Lyne as mother but I did find records for 2 boys and a girl with James and Mary as parents.
My info about my grandfather James' parents comes from NH marriage certificate and James Fitzgerald's death certicate. Both events in Manchester,NH. I'm stuck at this point and your Castleisland Lyne family just might be a connection!