I think we should go with him seeing her healing. It would probably create the most confusion for him, especially since she would not be out in the open during a full moon, so he wouldn't be able to see her changing or anything.
If you have the time and want to start it, you're welcome to, but I have to finish an essay and then go to class before I can do that. So it wouldn't be up for four or five hours, probably. I don't mind starting it, though, if you'd prefer.
As for Hadley, she is actually sort of wandering about Diagon Alley and things now, because she knows people who can help her get past the brick wall and everything. But maybe she is in the Leaky, supposed to meet with someone who has to cancel, and Alexander wanders in? If it's after he's met Nessa, they can talk about how weird stuff is. Or if it's before, Hadley can tell him about what she's learned. She won't know anything about werewolves yet anyway, so it wouldn't ruin the Nessa part.
If you want, this could actually be one long thread. Not sure if you'd prefer that or want to just do both.