The course of action is admittedly not a great one. I would have to file a motion with the court. The judge would reprimand him, but there likely would not be any other consequences. Based on his violation of the order, I could attempt to get a modification of the visitation schedule, but that wouldn't be guaranteed.
Before sending the text to H regarding overnight guests, I sent him an email recommending a custody schedule that was not 50/50, which is what he has been insisting upon. My proposed schedule ends up being a 60/50 split of visitation time, so it isn't that much different, but it provides fewer transitions for D7, which has been one of the hardest things for her. I was really surprised that I hadn't heard anything from H about it. He called this morning and told me that he had just gotten my message. He didn't seem happy about it and asked me why. I explained that I felt that it gave her more stability and a clearer "home base." He said that he understood that, but wasn't a fan of the idea. Then, he really surprised me. He said that he would "concede" to my custody suggestion if I would make a concession on the injunction against overnight visitors.
So, I talked to my sister, who recommended that I agree. I'll admit that I'm a little curious about WHY he's so stuck on that issue, but I'm trying not to let my mind go there. I don't think it would be a very beneficial place for me to get stuck, especially when I'm still feeling so detached.