Re: teaching the blind
I was at a seminar a few years ago for Sensei Jon Stokoes 40th year in aikido and one of the Sensei who was instructing was blind. I forget if this was from birth but it had been a considerable time and he leaned aikido while he was blind. He was really good, 2nd dan if I remember right.
He was also pretty good with his iaito, went through a few kata very well. All in all it was a pretty enlightening experience to watch this. Just shows that there are very few limitations.