Luffy will most definitely fight, but I'm not so confident in his ability to win at this point. & who does he even go against? If Brook can keep Big Mom at bay, which I think he'll struggle to do, then Luffy doesn't have anyone to fight. If Brook gets royally messed up on the other hand, then Luffy has his opponent, & it'll be great if most, if not all, of the homies have been nutralized so it's just Luffy and the insane big b!tch herself.
But then that leaves Judge and the Germa. Sanji might have Judge and his siblings to take down on his own, which I'm hoping he'll be able to do since we haven't really seen his strength post the time skip. The thing that has me worried is the small time frame this has to happen in, it'll be a whole lot of epic and not a lot of chapters for all of it to get enough coverage.