Your H should not be laying plans for the children without your consent. And telling the children before he's even told you, much less gotten your approvals, is an obvious end-run to cut you out of these decisions. (My ex does the same thing, to build up momentum for her plans before I can react.) If your H sells your children on his "plans" before you have a chance to react, then he's anticipating you will come off as the "bad guy" should you object at that point.
I'll repeat what others have already said: document, document, document. And do not let him get away with bamboozling you. It really s*cks that he not only got your S & DD enrolled into public school, but he did so in a district closer to himself. He is obviously using every means possible to stack the deck in his favor. Please don't go along with any more of his plans unless they are cleared with your L -- the only "peace" between the two of you that he will accept is if you are totally out of the picture with no alimony and no child-support and no children.
And your L is running out of excuses. First, she is out of pocket for all those days and weeks, and now she's saying the judge is not available. If she doesn't schedule an action soon, your H is going to run rough-shod over all of you with impunity. That is one L who needs a fire lit under her (and I thought my L was slow reacting!)