It's just an example of canon leaving the characters way too flat.
I think it's more like someone else said, the HP series are storybooks not encyclopedia's. We don't need to know about Vernon's Dad, Molly's second cousin, or Hooch's sister, because they aren't really important to the storyline.
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I think it's more like someone else said, the HP series are storybooks not encyclopedia's. We don't need to know about Vernon's Dad, Molly's second cousin, or Hooch's sister, because they aren't really important to the storyline.