1. Luffy will incorporate aspects of other martial arts but never the entire thing and the incorporated thing will b achieved in a manner unique to Luffy as with Soru n G2. I hope he uts a bit of Hasshoken into his style.
2.If he knew how much of a topic that is for his out of Japan fans he wld say so only to add some other line where it totally shows he was trolling like "and ussop is above WB" as he is a god though anyways Oda snakes out of such comments, the best he got to giving a power scale for the M3 was his Luffy 6, Zoro 6, Sanji 4 and that was lightyears ago.
3. cld happen but i kinda am not amped up about it though Ussop one of these days using a gun with conviction that wld b cool. Depends on the Zoan too i guess.
4. Everyone already does other stuff thats not their specialty like Zoro manning the look out post, Ussop and the miscellenious workshop, and Franky, Sanji or Chopper taking the helm, plus regardless of anyone's job they all put in combat hours on the log.
Let me project a what if or two of my own.
What if Hanckock is stalk..... ahh sorry i meant following luffy.
What if Cyborg Kuma got another df forced down his throat, wld everything explode or just the human parts. Also what if tgey fed it to his arm(mechanical parts), wld it if say was a bear zoan have a roar that repels everything.