Sounds wonderful! We lucked out with an awesome aide last year - she really got our 2E DD. When DD's psych did a classroom observation she felt that it was OK for her to finish the year in this school because of the aide. The aide made all the difference.
Unfortunately the wonderful aide only lasted a couple of months before resigning from the job. We had a truly toxic principal, though, and a really stifling school environment. The outside the box thinking of this aide made her very uncomfortable in this setting. It sounds like your principal is the total opposite so hopefully you will have better luck. Stay positive and enjoy the positive developments for your DS.
When we last saw the aide, DH muttered that she wouldn't last long at this school. She is too competent and rational. She continues to be fantastic. I agree, she won't last long here and will go somewhere else probably.
We'll enjoy her while we can!