Timmy , It would be much better if you added a lot more information, Your Daughter's age, were you and the mother legally married, are you paying support, when is the wedding ( it may already be too late to sort sort visas) etc, The Child will only be half Irish if your name is on the Birth Certificate?
It all depends on what the Airline think is and onward ticket. I don't think that any real coach lines actually travel across borders. Rather you get off and walk to a connecting bus etc.