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.
It’s certainly possible, but we know of at least three entirely separate, completely unconnected and contradictory sequel trilogy ideas he’s had over the years that have been very publicly known to be separate, and were thought up at very different times, decades apart. Plus, we know there are more than just those three, ones that we just don’t know the details about.
It would be really weird if they were spending the whole book dancing around a core concept of this sequel trilogy, it’s more believable that this is just a fourth idea.
I love George and thank him immensely for creating something that’s brought me so much joy my whole life, but in my opinion Star Wars is at its best the more other people are allowed to play in his sandbox.
100% agree.