Have to hold my hands up and admit I havent read all the thread but it seems as though you are making a success of things.. Its just that people see success in different ways..
As coaches/people who have been in your position we appreicate the job you are doing with these kids returning each week and smiling throughout..
Others will not (and that maybe includes the players)..
Kind of hard to suggest things to work on without seeing you play/train but I'd make sure that they all know what you mean when you suggest various things (as MikeyN suggests) as this is something that gets taken for granted and some may be a little embarrased to hold their hands up for fear of looking a little silly.. I have seen it with adults who nodded their heads approvingly and then didnt have a clue what was being asked of them..