(i didnt read all the posts)
I heard that people with special needs (like deaf, mute, paralyzed etc.) sometimes have that disability because in there past they did something wrong with that body part (ex: mute – spoke a lot of Lashon Hora) and Hashem allowed them to come back with that disability so that they wont be able to do that sin when they come back and this way they will have a ‘kappara’.