Interesting article here by Padraig Og O Ruairc on the Hibernian Rifles, a small little known group that participated in the Easter Rising.
A Short History of the Hibernian Rifles 1912-1916 | The Irish Story
They originally emerged out the Ancient Order of Hibernains but split with them because, a they were not militant enough and b, many working class Hibs in Dublin were against the Organisation's anti-union stance during the 1913 Lockout.
Around 20-30 of them took part in the Rising.
See also, for the day that's in it; The Irish Story archive on the Easter Rising | The Irish Story