Thank you for sharing your experiences. I know that emotionally as well as mentally, you went through the wringer.
I suppose, if I was trying to point out the bright side to you, which I am, monetarily, your oldest will soon be of age and your support will go down. Hopefully some of the CC's will pay off, and as you progress, your income will increase. Not to say you don't have a tough row to hoe the next few years.
A little advice, if I may, from a Mom's POV:
You mentioned your D is trying to express her feelings. Encourage her, but don't push. And as far as the son who takes things in stride; I believe that is a defense mechanism. Don't take it for granted he is doing okay. My youngest uses the same defense towards her Dad, and she's 23. Your eldest, you are exactly right about. The eldest is usually the closest to Mom emotionally and has the hardest time. Do not fall into the trap ( as my XH did ) that as he grows older and matures, he will see it from your side. Keep trying, gently. Never let him be able to think that you 'abandoned' him. You may have to grow an Armadillo shell to counter all the rebuffs, but he will always know you were there, and trying.
Now we hold our breath as we wait for all the pieces to fall and settle into place in our new lives. I have not seen my settlement on paper either, so there may be more battles ahead. (Sigh)