May a lay reader take the part of the Christ in the reading of the passion narrative during Lent and the Triduum or is this role reserved to the priest?
The rubrics for Passion Sunday and Good Friday are quite clear on this question, as reflected in the 1988 Circular Letter Concerning the Preparation and Celebration of the Easter Feasts from the Congregation for Divine Worship and Discipline of the Sacraments:
"33. The Passion narrative occupies a special place. It should be sung or read in the traditional way, that is by three persons who take the part of Christ, the narrator and the people. The Passion is proclaimed by deacons or priests, or by lay readers; in the latter case, the part of the Christ should be reserved to the priest."