CK I know that you are feeling attacked and people are trying to pick on you but they bring up some seriously valid points and seriouis concerns.

I know for a fact that you want nothing best for Abby and her riding career however far she wishes to take it :-) . If you want your daughter to do well and excell in whatever aspect of riding she settles on then I highly reccomend you reconsider this person as Abby's instructor. Any instructor who emails a parent ( let alone emails a email like that one ) to get their child to understand riding and the various aspects deserves shooting in my books lol . It is HIS job to teach Abby and it is HIS job to help her understand in a clear and concise manner what he expects of her and what he wants to teach her. By emailing you he is effectively shifting the responsibility to teach Abby to you her parent , the person paying HIM to instruct and develop Abby's abilties as a rider.
He is not TEACHING her by doing this ! If he really wanted to show her the things mentioned he would do it himself! He would get on a horse and demonstrate it to her, he would take her to various shows from the tiny BYB shows to the big ones to show her varying styles , riders, the do's and don'ts etc. He would not be emailing YOU as her parent asking YOU to basically do the job YOU are paying HIM for ........

Please do not take this as a attack as it is not meant that way. I want you to realize that I want nothing but the best for Abby and her journey through learning her displine and being able to ride to the best of her ability and by staying with this coach I have grave doubts that this will happen and that he will teach her things that are so utterly wrong and basically set her up for failure in the future and set her up for a big let down when she does eventually get to show her ass off in the future !

Please reconsider your choice of instructor and see if there is anyone else within the area that you can research, get refrences for and get her in with them if it is affordable to you