These are great! You did everything I would have suggested. You shot at a high shutter speed, went wide on aperture, and used an appropriate ISO to compensate. Your timing was excellent! My only comment is that in the first photo there are two pieces of paper or tape on the floor that can be easily removed via Lightroom or similar tool.
I shot ballet for one school year, shooting tech rehearsals and performances. If you go to the link below and scroll down, you'll see four ballet albums.
http://grahamglover.zenfolio.com/f593136965
Here are a few things I did.
Exposure: I always shot manual. I assume from your settings you did, too. My exposure approach is probably similar to yours. Shoot at the highest shutter speed you can to freeze motion, and keep the lens fully open. When going through my performance photos, I see I shot at 1/320s. I think 1/500s, as you did, is better. ISO was what I used to adjust exposure. On the 5DM3, I used the "Set" button for quickly adjusting ISO.
Autofocus: When the action gets more complicated, the AF system on the 5DM3 is excellent. I used AI Servo. Unlike sports, I used the Zone AF area selection mode for tracking dancers, especially as they move across stage. I don't recall which "Case" I used, but it was probably Case 4. The point is that you should feel free to explore and use the AF capabilities of the 5DM3. Canon put out a guide on AF for the 5DM3, linked below.
http://cpn.canon-europe.com …rkIII_eng_January2013.pdf
I hope this helps. Have fun!!!