Solost - you absolute STAR! Seriously. I have gone all misty-eyed as well - you did so very well and I too am proud of your achievement today.
Your DC sound like wonderful little troopers as well (no doubt thanks to you!) and I am glad that it went better than you thought - I bet it's a weight off your shoulders, and theirs!
Your middle DD may be one who likes to think things through while being active, rather than emotional outpourings - but as someone else said (and you already know), keep an eye on her. How did she respond when you spoke to her on her own? Did she have extra questions for you?
So your H has realised that all his threats, bombast and bluster had and have no effect on you. That is a massive bonus! He will have to tread more carefully in how he deals with you now.
Miraculously he appears to be all better now - but as he has lost control of the situation, and you, he may continue with the MH issue, whether or not it is genuine. If he does phone/turn up suggesting all is not well in that department, refer him to his GP for treatment and tell him you will be calling his parents to let them know of his deteriorating condition so that they can ensure he calls his GP. If it is fake, that should put a stop to it. If it is genuine, that's the best advice you can give him anyway.
I sincerely hope he turns up for the DC when he says he will - but the chances of him keeping his word fully are slim (on recent history). I expect he will show for Christmas Day, for a while - but I hope you decide to have it at home rather than the restaurant because I still think it would be better for you all. Perhaps you could get a takeaway!
I am chock-full of admiration for the way you have handled this and fully believe that you are on the highway to recovery. Do take some time for yourself to accommodate this change though - make sure the foundations are solid.
big [squeeeeeezze] to you - well done!