Momo,
I think you made a great point about adjusting your coaching to meet each kids individual needs. If a kid doesn't understand what their body is trying to tell they will struggle to learn. Some kids can catch on and learn very quickly, those that can't have a tendency to get frustrated watching their peers move onto something else. Bottom line is the player and the PARENTS have to put in the work to get better.
Well put!
Without trying to sound redundant, coach them from where they are AT, not from where you want them to be!