I know Kishi is on a roll with debunking our theories, but this is just too bloody far
What are you talking about? I'm batting a thousand.
I am not sure that she would be talking to Kaguya, though. I imagine we will likely get a back-story where Hiashi tells her, going into the war, of the history of the Hyuuga and their link to the Uchiha.
The rumor that the Byakugan spawned from the Sharingan had to come from somewhere other than Madara - and if the origins of the Sage were shrouded in mystery - then it can only be reasoned that the Hyuuga, as the oldest clan, knew far more than they were letting on.
Thus, we'll get a flash-back that deals more with the Hyuuga and their lineage. Probably right before Hinata chows down on that fruit.
Though it could go either way with her and the fruit. The main thing is that the fruit needs to be neutralized and the person who receives it (assuming one receives it) needs to not become conceited.
I suspect Kishi will bloom the fruit as a point of building plot suspense and Hinata will come out of nowhere and nom-nom while Madara is off being arrogant somewhere.
