Blu, my first impression of what you wrote last night was that you were advising Leah from a very black and white place.
I don't think showing him kindness and spending time with H was weak on Leah's part. I think she was strong! She essentially said "Yup, buddy, while you've been spending time with trash, I've been here, beautiful, strong, loving, funny and kind. I'm still Leah and I always have been."
To me, that's what her time with her H was about. Leah showing H she'd reclaimed her identity and showing H she's fine without him. She held up boundaries with him. She didn't fall to pieces. She was strong.
I totally agree with you that it takes time to see changes. However, how will Leah know with her circumstances? They are long distance and they don't share minor children, so she can't just sit back and let time do it's thing because there is no regular interaction to see the pattern you're telling her to look for. You had children with your H, so it could happen over a long period of time and without having to actively choose to see him or talk to him.
I don't see how Leah can see evidence of that consistency from her H without being somewhat responsive to him, due to her circumstances. The only way her H could start working his way back is contacting her, exactly what we're seeing him do (though we don't yet know his intentions.)
I also think that WH/MLCers are not going to throw it all out there without some indications that it is safe to do so, since shame is such a powerful driver with them. Those who share kids might be able to demonstrate receptiveness on a regular basis, but Leah doesn't have that opportunity. When he starts sniffing around, she's got to decide how to respond, because it could be the start of that consistency. And there's no other way for her to know.
I think Leah's situation requires her to be more receptive than those who share minor children, just because there is no opportunity for regular interaction that could allow her to passively observe him.
I'd be concerned if I saw that she was emotional or didn't have boundaries, but she's doing really stellar with those things! Her H asked to come see her and she didn't immediately jump on the opportunity, and that's a great thing. She's protecting herself, which I think is the common thing that all of us want for her.