If Jimbei really leaves Who's Who to Brook but at this point I doubt it. Yamato seems like she has a better chance facing Jack then Jimbei dropping everything and heading for the Scabbards. Plus, Sanji could give Yamato info on the Scabbards once they meet up. That's thing Jimbei was informed about was Robin heading into a trap. Wouldn't he head there first since he saw it as trouble for Robin?
I'm a supporter of Zoro vs King (after Zoro accomplishes something significant against Kaido, well something more significant than what he's already done so far). Sanji vs Queen is incredibly likely.