They are brothers and sisters MÃ ire , CiarÃ n , and PÃ l Brennan and their uncles Noel and PÃ draig Duggan . Clannad comprises siblings Moya Brennan , CiarÃ n Brennan , PÃ l Brennan ( , who left in 1990 and rejoined in 2011 ) and their twin uncles Noel Duggan and PÃ draig Duggan .