1.It has ballet and Phantom of the opera elements?
This manga is about a black hair, she goes to a prestigious academy for the arts, there she meets to boys, a blonde and a black haired boy. They become her phantom of the opera. In the end the boys(or so it seems) die and she become very famous.

2.This is a oneshot:
Whats the manga about a girl and boy that grow animal parts because of a chemical a mad scientist spreads. The girl grows cat ears and a tail. The boy grows dog ears. But in the end they turn out to be wolfs ears cause he pounces her. They are in love with each other.

3.In this story the land is divided by different tribes. Its something like the heaven people, and forest people/ sea people or something like that and they don't get along with each other. In this story you have this heaven tribe girl who lives in a very tall building , she is like a princes or something. She escapes or runs away and she meets a boy from the forest clan or something. Her enemy sort to say. It seems the forest people have like esp, and that why they were called monsters or something. The girl and the boy fall in love with each other.

2. Probably the last extra oneshot in Anata e no Crescendo

#1 sounds like Le Masque.

#2 Maybe it's http://www.mangaupdates.com/series.html?id=63412
not sure about that though