Since The Star Wars Archives has George talk about the Whills I've included this in the Literary discussion. How would the characters learn about the Whills? How would they react?
I would assume there would be a catalyst to cause them to travel to the Force planet (Wellspring of Life) where Yoda went in TCW- maybe there's an enemy who is trying to learn from the Whills, and the heroes must stop them? I'm sure the Force ghosts would be around to tell Luke and the others about what the Whills are and how their knowledge can be used for good and possibly for evil- and George would have had no qualms including Ewan and Hayden, not to mention Qui-Gon Jinn.
I think it would probably be part of showing the training of a Jedi Knight. If we got to finally see Luke train a new Jedi, I think that would be the avenue for introducing the audience to the Whills and generally to the ecological ethics that Lucas built around them and which form the core of Jedi ethics too. There would probably also be additional metaphysical elements related to the Whills that would relate to how Jedi learn to live after death in the Force. But I’m not sure we’d necessarily see the story fully focus on them.