It sounds as if you handled things very well. As for her email, it is very common for the WW to talk this way right after she sees that her H is not going to fight with her and is willing to set her free. She had some old feelings to rise enough to make her feel conflicted, but not to the degree she is willing to choose her H over her friends.
So, I suggest you not give any weight whatsoever to her email. It is no more than a temp check to see if you will nibble at her bait. If you feel you must respond, then just say, "I agree", and leave it at that. It will hit her hard to see that her little crumb of "torn feelings" is not enough to make you jump to pursue her.
When a woman is really in love with her man, she' ll give up every friend she has for him. He comes first with her. No friend, no GGW nights, ........nothing comes before her man. And, the woman in love will be willing to do most anything to be with her man. In the email, she clearly says she isn't going to change or give up her friends. She experienced some old feelings, but not nearly enough. She's not ready to put her MR first.
She came back over later that night. I just told her I got the email and I didn’t know what to say and left it at that.