For the Post-game Hala battle, I just mainly relied on my Necrozma's (Not Dusk Mane, since I got US) Photon Geyser, but I also used my Dusk Lycanroc and Incineroar as back-up. But, for the Kahuna battle early in the game, I used both Butterfree and Cutiefly (since they both double resist Fighting and can use moves that are supereffective against them).