I know how these things can raise the anxiety level. As an option don't discount asking your STBX if you can negotiate a lower settlement on the value of the house. Simply state what you have here. Your parents are helping but it will leave them without the safety net they desire. All he can do is say no.
I know you are going through this and there is undoubtably uncertainty associated with it, but my experience has shown that honesty and patience are two wonderful allies in these negotiations.
Glad to here your DB "tools" came in handy, you will find them creeping into your life when you least expect it. Why? They are part of the reward for making the effort!
Enjoy the heck out of your holiday! Tell us all about it when you return.
