Getting into the new novel, Resistance Reborn, which is sometimes billed as the Avengers of the new expanded canon because it brings together so many characters. So far, that's definitely the case. It's an unapologetic fanservice piece that so far in my reading has really dipped into the Aftermath books, Inferno Squad/Battlefront 2, the comics, and Bloodline. It has even referenced a Leia junior novel.
I don't know how it will turn out, but I'm growing convinced that some of these characters will cameo in Episode 9. Nothing to distract from the movie, but just Easter eggs for those who have enjoyed reading about/watching/playing the likes of Norra Wexley, Black Squadron, Rebels, and Inferno Squad.