At the moment we have one 21 year old with downs syndrome, one 19 year old in a wheel chair, one blind and mostly deaf 14 year old, and sense last week, an adult with no use of his right arm (he did one handed push ups first class!) enrolled at my school. I honestly don't know what the best way to teach them is, but I can tell you what we've done.
Answers to your questions:
1) Yes, we teach them differently. They all require more attention from the advanced students. With slow students, we take it slow. With physically handicap students, we change drills and sets and forms to accomidate their physical differences.
2) Yes, we have different belt requirements fro these students. I don't think that there has ever been a need to explain to other students, they are very understanding.
3) All of the students I just mentioned are now included in the regular class. The blind and deaf student started out in private classes, but is doing just fine with the rest of us now and has improved tremendously with the intergration. We assign one or a few advanced students to guide him and work with him each class.
4) We teach them as much as they can handle, which is obviously less then the other students.
5) Hmmm. That's a tough question. The deaf student has cocliar (sp?) ear implants and has whoever is assisting him repeat instructions into his right ear. I think it would be great for someone to learn sign for a student, but I think it would be easiest to show without sign, or assign a private class to the individual. For that much extra work though, there would probably be some sort of compensation from the student which is hard for a lot of people to come by.
6) Basically the same curriculim with accomidations and modifications where need be is used.
I would recomend considering a few things for the benifit of these students, and the ones helping them. Do not make them feel like a burden or chore. They know that they are different, and it is something that they can automatically be very self-conscious about (even though it is not reality). Make sure that every advanced student knows that these students are picked FIRST in drills and sparring, that is a huge responcibility. Also, it is not just self deffense they are working on in class, it goes much deeper.
I personally have a tremendous amount of respect for these individuals, especially the ones with physical disabillities. It takes an incredible amount of humility and drive to participate and overcome tough situations. They are extremely inspirational. I look at them and then take a look at my life, and thank God for all he has blessed me with. I don't know if I could do what they do if I was in the same situations.
Bryce, Sam, Von, Jason, if you're out there you are an inspiration to us all, and you are stronger people than I. Thanks for giving me the oppertunity to work out with you.