Most likely 2 male melanurus wrasses will fight in the same tank. If you were to get 2 females and let one turn into a male, this would be a much safer solution.
Yellow coris are pretty peaceful. I have seen multiple specimens coexist peacefully in a tank numerous times.
The green coris is usually pretty aggressive for a Halichoeres wrasse and usually loses its bright green coloring and ends up a very pale green. There are exceptions but very rare exceptions.