#1 - You are setting your daughter up for a fall. Are you willing to risk her getting bad grades for your cause? Simply using a non-approved program will probably do that.
#2 - The people who made the decision to use MS aren't real bright, but they ARE in trusted positions. You aren't. So your letter campaign will be tossed aside (best case), or used against your kid (worst case).
Do what I did when I thought the school board was doing something stupid in tech. Show up an a board of education public meeting. Make friends. Speak publicly, stroking their egos, while at the same time establishing your tech cred. Make a connection with a board member. Thought the member, push your agenda.
I found a board member that wasn't technical and was getting snowed by the IT crew. She latched onto me as her tech resource, and then we worked together.
Unless you are willing to invest the face time, the attendance time, and show that you are willing to hang out REALLY late into the evening when they vote on budget issues and don't want the public there, then you can be ignored.