Róisín Ní Shé not only had a daughter named after herself, but a daughter named Nessa/Neasa, which was the name of one of Róisín Ní Shé's four sisters. That daughter is still alive, and although married with adult children, she still goes by Nessa Ní Thuama.

And Nessa Ní Thuama's children include three brothers: Eamonn, Fionán, and Cormac de Barra. These three, at least, are musicians, and at least two of these three have worked extensively with Moya Brennan of Clannad. In fact, Cormac is the harpist out of the three brothers, and his grandmother Róisín Ní Shé was among his harp teachers.

About the father of the brothers De Barra, all I can find in my searches is that Cormac, in an interview, states that his father was a musical director in the theatre.