Was Fr. Perez validly ordained?
Fr. Perez was ordained by the late Alfons Maria Cardinal Stickler, who was a valid priest, but was "consecrated bishop" in the new (invalid rite) of anti-pope Paul VI.
If a priest has the fullness of the priesthood, than Fr. Perez is valid. If it takes a bishop to validly ordain, than Fr. Perez is not valid.
There is a posit that a priest has the fullness of the priesthood, but that an interdict has been placed on him. This means that a priest has the power, but not the permission to ordain other priests, and that the title of bishop is merely an office. I would really like more information regarding this. This topic seems to be shrouded in mystery.