Ahahaha. It's fine. I get how it can be when you get swept up by a game. Happens all the time. It literally just consumes you.
Astoria - Yes, they would know each other by association. But, as it goes, Arden should like the Greengrass well enough. They might not be close, but they're pretty much part of the same circle more or less.
Lavendar - Good idea. Arden won't bother those who don't bother her. Well, unless she's assigned to take care of them. But I think Lavendar should be safe for the most part.
Bill - His wife's disappearance has nothing to do with her and she frankly doesn't care about the going ons of the Weasley family, so there we have it.