Whose to say they’re seperate treatments? They could be part of the same story treatment as the Whills storyline but he didn’t feel the need to address it further since he already discussed it with James Cameron.

Paul Duncan also addressed this indirectly with Rick Worley when he said that he looked to ask George new questions instead of ones that already had answers.

This new information is only a fraction of a greater whole as we still don’t have information about the grandchildren, Han’s role in Episode VII other than he dies, and loads more. The book also has more information than has been shared on the internet. So we’re only seeing a broader picture of the story.

The only really “contradictory” thing he seems to have stated over the years with the Sequels is Luke would have a love interest but even that hasn’t been confirmed or denied to be a thing. Nothing else he’s said really contradicts any of his other Sequel ideas as we just don’t know all the details. He’s a creative though. Creatives change their mind.