Her attacks are either a) her lashing out in defensiveness because she is feeling guilty, b) trying to continue to exert control over you by showing that she can influence your emotions, c) her trying to cause you to lash out and give her ammo, d) her rewriting the narrative to fit her internal rationalizations, or e) all of the above. Note that none of these reasons is actually about you.
Whatever her motivation, the best response is to not let it bother you and not respond to the crazy. If she sends a 3 page tirade that has some unilateral decision regarding your kid's schedule hidden in the middle, respond only to the schedule change, ignore the rest. The more you respond the more it ramps up. If you ignore it, she will give up eventually.
Also, as far as the kids school, I suggest you take the initiative and sign her up for your preferred school as early as you possibly can. It will be up to your ex to try to change the status quo. If she is really going to be moving 20 minutes away, that's her decision and she can do the driving unless she can convince a judge to change the school registration for the sole reason to force you to drive instead of her. There's very little chance of that happening.
