OP, this thread has really stayed with me. I don?t know if I?ll have anything helpful to say, but sometimes the obvious just does need stating.
Stop. Just stop. 
I can feel from your posts that you are caught in a perpetual thought process of ?what ifs? and ?can he? and trying to cover off every permutation of an already complex situation. It?s not possible to have an answer or plan for everything. If I could reach through the screen and grab you I would (for a hug, not as in a mugging 
).
You only need to think about things that are happening, things that are factual and things that are sensible to consider. Being sued for libel on MN? No.
You know all this:
He?s a shitty little bully. You know what is normal behavior. You know that people who are upset can behave badly. You know he is acting way outside these parameters. It?s because he is behaving so badly that you doubt yourself. Don?t. You are normal and he is not.
This is not you. From this thread you come across as considered and self-aware. I looked at some of your other postings and you are informed, rational and practical. I bet you don?t recognize yourself at the moment. Please just re-read your thread as though it was someone else?s. There are some obvious things for you to do and you certainly have the capacity to identify them.
You know all this, too:
Contact centres. Someone upthread mentioned these. They sound ideal, especially if they can be used for handovers. Saving that, meet somewhere neutral and have someone else with you. If you are feeling vulnerable to misrepresentation (which you are right to), then refuse to get into any situations where it would be your word against his. That?s just common sense. I don?t know about court orders and their implications, but others on this thread clearly do. Make sure the line legally drawn in the order is not blurred or crossed.
RL support. I don?t know if you have friends or family close by. If possible, nominate someone for all contact to go through. In my experience, help in this way doesn?t have to come from someone super-close to you. If you know anyone who you think would be good for the role (ie just a little scary and strict ? maybe another mum you know) then think about asking them. If you ask for specific help from a specific person people are often only too glad to do what they can. And you can time-limit it to, say, the next 2 months so the person knows what they are committing to.
The house and the locked room. Tonnes of scope here for endless speculation about what you could, should, shouldn?t, might, won?t etc etc etc. Alternatively, you could just ask your lawyer what the law says (and it will be quite clear) and stick with that. Then that?s a whole chunk of angst off your plate.
Finances. His ludicrous sounding secret-squirrel financial doom-mongering aside, do you have access to financial information? Hearing that you have sizable assets ?as far as you know? is very vague. Do you feel you?ve been as savvy as you can about finding stuff out? Maybe you?ve had legal advice on this already and are okay.
Talking shite. You do know that he is making up the law as well as twisting your interactions, don?t you? Disclaimer here in that I am not a lawyer but in my job I deal with people who are domineering, often bullying and have made up their own moral code. When you call them on it, they often get all legalistic both in their tone (I hereby, therefore, the undersigned, notwithstanding, without prejudice blah blah blah) and with references to random statute they have heard of. It?s irksome (because they still think they?re oh so clever), but good because after that it really is like shooting fish in a barrel. I?m always amazed that bullies chose something as well documented as the law to blag. They?re only embarrassing themselves, although I?m incensed that it does intimidate a lot of people and they get away with it. You know it?s bollocks, or you know how to Google and find out.
Take the piss. Jengnr is totally right and it?s a great way to undermine him in your head: from someone who intimidates you to someone unmasked as a phoney, and subsequently his power diminishes (think Scooby Doo baddies, or the Wizard of Oz (if he was also a twat)). The key to this is to be totally juvenile and keep it as a private joke to yourself. Examples: Benny Hill ring-tone for him, read out all his texts aloud in a whiney baby voice, remember his worst pair of pants, imagine what he would do in his ?special room?. I?m sure people have other ideas that helped them, too. A friend and a bottle of wine works well.
It wont be like this forever. Frequent advice is to take one day at a time, which is valid, but beware of trying to solve a year?s worth of problems in that one day, every day. It?s exhausting, so don?t do it.
Yes, you have decisions and choices, but a whole load of other stuff will just happen. The world keeps turning, so why not live today but with half an eye on, say, 3 months time. Think about where you might be in 3 months ? not a target or a challenge, just what you think your life will look like. Then in 3 months look back and see what?s changed, what hasn?t, and what the next 3 months might look like. That way you acknowledge the little improvements you would otherwise have forgotten about, plus you get better at managing your own expectations of resolution. You?ll feel more in control.
Christ, I?ve gone on! Sorry about that. I hope some was helpful.
PS ? my mum would call him a pompous little twerp. ?Twerp? always makes me smile ? so dismissive!