For PangPang:
I do not fully understand your goal. Are you doing a research or just want to buy a camera?
I think some people are fun of Nikon and some are, of Canon. Just buy the brand you like and either will do great work.
I use canon camera and would suggest Canon 5D Mark III even though I do not have one.
Some secret: Your teacher said she is going to buy a 5D3.
I will recommend Nikon D600. It is about 2/3 of the price of Canon 5DM3 and is on the same level of 5dm3 if is not even better. Compare to body the lens are much more important. I will recommend Nikon 24-70 2.8 and Nikon 70-200 2.8 VR. They are about three times of the price of the body. The lens will keep its value or may be increase its value but bodies are always decrease is value.
As for color if you have the correct exposure the color is always right no mater which brand of the camera. Of cause there are personal reference.
For stage photograph : set your ISO to auto ISO with acceptable level, use S or M mode to ensure the shuttle speed, use spot meter because the light changes so fast. set the white balance to auto because normally you don't have time to mess with the WB.