I finished Leia: Princess of Alderaan and there were a few Last Jedi hints:
- Crait was the sight of a Rebel Base set up by Bail Organa. The white stuff is salt over red soil.
- Amilyn Holdo was with Leia in the Apprentice Legislature and colors her hair a lot. She’s into astrology of different planets and is a bit loopy. It’s implied that she will join the Rebellion as she supports taking action against the Emperor is the only option left.