Like I said, there are lots of possibilities. What will the rest of SHs do? The rest of Revos? The SH alliance? The others who might join the fight: Law, Croco boy, Boa, Hawkeye, Weevil, Urouge, Bonney, possibly Kidd. What will the SWORD do? I lean towards the possibility that SH won't fight Admirals.
Garp vs Sengoku
Dragon vs Kong
The East blue 5, Sabo, and the grand fleet fight the Marine Headquarters.
Luffy vs Smoker
Sabo vs Akainu
Zoro vs Fujitora
Sanji vs Ryokugyu
Usopp vs Chaton
Nami vs Momousagi
Cavendish vs Tashigi
Bartolomeo vs Coby
A group of the straw hats with the Heart pirates will fight the cipher pol agents as they attack mariejoa in search for knowledge of the D and freeing the slaves
Jinbe, Vivi, Robin, Brook, Law, Leo, Don Sai vs CP0
Another group will fight against the SSG created by Vegapunk alongside the Kid pirates
Kid, Killer, Franky, Chopper, and others vs SSG
There’s plenty of people to fight. But the main force (the admirals) belong to the main force on Luffys crew.