The Monster trio doesn't include Luffy.
Luffy has left the others behind and it's a yonkou style crew now.
Captain: Luffy
Top Commanders: Jinbei, Zoro, Yamato, and Sanji,
MIddle people: Franky, Brook, Robin, and Carrot
Bottom people: Chopper, Nami, Caribou (if he joins clearly), and Usopp...