My first thought was "Weasley" and I am a HP nerd.
This. But I don't think it's weird or bad. Especially since Molly is only DD's nickname. If you introduced me to your children, Molly and Arthur, I would probably immediately bring up HP. If that bothers you I wouldn't use it. The good thing about Molly and Arthur though, is that they are not names that are so specific to the books, like Hermione or Sirius are. So really only HP fans will get the reference.
Re: (Untitled)
This. But I don't think it's weird or bad. Especially since Molly is only DD's nickname. If you introduced me to your children, Molly and Arthur, I would probably immediately bring up HP. If that bothers you I wouldn't use it. The good thing about Molly and Arthur though, is that they are not names that are so specific to the books, like Hermione or Sirius are. So really only HP fans will get the reference.