GB, I agree that a remorseful WW is unlikely, and if she asks I can see the value in clearly stating your boundaries.
My only concern is how high the expectations of the LBH are. If a WW mentions something about working on the marriage it can often be a temperature check to make sure they still have the LBH on the hook and can cake eat and avoid consequences.
In DR Michelle talks about being very cautious to show too much eagerness in this spot, and talks about moving slowly, not giving up your detachment or LRT. I think if WW asks about working on the M it's ok to answer slowly, like it's an idea being considered, and then state those boundaries. And then it should be presented almost like it's no big deal either way, if she's not interested then no sweat, keep moving on, you're the one that brought it up.
If, on the other hand, LBH immediately lists the NC letter and other boundaries, then shows emotional attachment to that outcome, pressures her, persuades her, and brings it up again and again...all he's doing is having attachment and expectations, and interfering with her journey.
Me:38 XW:38 T:11 years M:8 years Kids: S14, D11, D7 BD/Move out day: 6/17/14, D final Dec 15