Revealing mistake: When the crocodile attacks Sue from the water, it holds on to her canteen for two shots. You can see that the animal actually holds on to a prepared version of the canteen - it is cut in half, with its lower teeth inside to hold it more "comfortably" during the pull.
Continuity mistake: At the beginning when the helicopter lands, the helicopter's shadow goes out toward the rear right of it (from the pilot's perspective), but when Sue grabs her bags and walks to Walter, the shadow is now cast to the front right. Since Sue got out and was standing next to it, the helicopter did not move in the meantime. (00:03:15)
Answer: It is a party thrown by one of Sue's socialite friends, presumably the husky-voiced woman whose crotch Mick grabs. The party is not "full of hookers", Simone is there as the hired escort of the old man she is dancing with, who Mick naively believes to be her father. We can assume the old man paid for Simone to be his date to the party and likely for some time alone with her afterwards. There is no stated reason for why the party is being thrown.
BaconIsMyBFF