RE: Does Pilates count as
I think a rest day is whatever you want it to be. It ideally should allow your body to recover from your previous work, whether that be strenuous cardio or weight training. The idea is to give it time to repair. For some people, that means "active resting" where you just do something completely different, and that either doesn't stress the body at all, or stresses it in a totally different way. I often do yoga on my rest day, and keep it non-strenuous. Pilates also sounds like a great alternative.
Sandra