>2. Can the part of Octavian (what a wonderful role) be sung by a countertenor?
No. A countertenor doesn't have the range required to sing it, doesn't have the warmth of voice needed,
and the wrong sound to blend in the music with the others. The trio at the end needs three female voices,
the voices intetwine so that it is sometimes impossible to tell without a score who is singing what.