Thinking of you and your family. I think you all are going to be better than ever, though it may take some time. You're in the middle of a reshuffling of relationships that would be bound to happen anyway as they transition from relating to their dad as his kid to relating to him as an adult. They're going to judge and question his choices in the process of figuring out who they are.
I think it is so cool that you and H work so openly on problems and have such an attitude of strength in seeking help from others. It's such a good model for your kids, no matter what the relationships end up as, because they can see how you TRY. They can see what the tools look like. They're not going to be afraid to use them.
You mention your D's biting wit often enough that it seems to bother you more than the typical parental eye-rolling. You might try setting boundaries that make it more desirable for her to restrain her mouthiness. I'm no pro at that, but I think if you had some action you'd take, such as reducing her curfew 10 minutes every time you think she crossed the line... I'm sure you've already been doing something like that. I need to listen to my own advice too, because S12 can really work on my last nerve.
You're being a really great mom to work so hard at these relationships, I hope all goes well with the C!
Adinva 51, S20, S18 M24 total 6/15/11-12/1/12 From IDLY to H moving out 9/15/15-3/7/17 From negotiating SA to final D at age 50 5/8/17-now: New relationship with an old friend __ Happiness is a warm puppy.