Kaido coming back and getting defeated again will be included in the booklet
The long lost Yonko and maybe Admiral/Logia awakenings, Zoros parentage, Roronoa history, why Kuina and Tashigi are so similar, stuff about Sanjis mum, Namis parents, lineage, why she was at Oykot, Usopps full name and lineage, Frankys parents and lineage, Brooks past including as a convoy and knowing the Vinsmokes, Peronas full name and bsckstory, lineage etc, Mihawks backstory, Tokos full name, parents and such, Tamas full name, Kaidos full name and missing backstory, why he looks so different to Oars, Yamatos mother, Who's Who's face and real identity, judge's eyebrows, judge's speech to big mom and germas ancient history, the list keeps going on and on.
But who I am kidding? How much of these will actually get answered even in these manuscripts or by Oda in anyway possible?