I'm not normally in favor of Henry Crawford, but I can see the potential in redeeming him. However, I think Henry is still a controversial character, wavering between selfish and unselfish motives. This decision to tell Sir Thomas about his flirting with Maria and Julia is obviously unselfish, but I still can't see the whole of his love for Fanny and his behavior as completely unselfish (he manipulates Fanny several times in the previous part).
I wonder where you are taking this - both for Henry and Fanny and for Edmund and Mary. This reformed Henry might deserve Fanny but I can't see this Mary deserving Edmund. I can see Fanny better off in marrying Henry (who would help her character to develop in a new direction) than this impossibly obtuse Edmund who would only hold her back in spite of the seemingly helpful concern.
Thank you for continuing the story!