If they made this an anime arc, they'd bring the travel companions back from the other regions to fight off the members and leaders.
Misty vs Archie
May vs Maxie
Dawn vs Cyrus
Iris & Cilan vs Ghetsis
Serena & Clemont vs Lysandre
Gladion vs Faba
Alola cast vs Rainbow Rocket Grunts
Ash & Brock vs Giovani