If Nan moved into my town, I'd smile because she's so cute and keep her for a while. Ultimately, however, I would give her up because she's not a dreamie of mine.
If Shari's house plot appeared in my town, I'd be OK with it, actually. I don't really see why people don't seem to like her. I'd let her go if she asks to move, but only because I need my Dreamies.