everyone knows Luffy is in Wano
How so?
Weevil may not necessarily come for Marco. He could come for Luffy, who he already showed an interest to
This still leaves the problem of getting to Wano and then to Onigashima.
It was a general statement dude. It was to say the live floor is in need of help, so they need to go there.
He told Sanji to head to the Live Floor:
If Zoro wasn't to play any role on the live floor, Oda could have easily made Sanji drop Zoro somewhere else.
Oh come on, you can't really believe this. Who was going to heal Zoro if not Chopper/Marco. Zoro is at the Live Floor for healing. Even if Zoro was heading straight to Kaido after recovering, he would still get healed up first.
Luffy vs Kaido battle, where he has full trust in his captain
The last thing he heard was Kaido declaring that he defeated Luffy. He never heard Luffy reaffirming that he would win.
Which is enough for Zoro to have more concern on the live floor himself implied to be in need
Let him show that concern. Let him actually say that
he wants to help there.
The best we have is Zoro telling Sanji to help out at the Performance Floor. That's not Zoro saying that
he wants to help there.
Simple, he could help to stall Kaido the time Luffy comes
Yamato is currently doing that:
Do you expect her to get quickly defeated?
As far as conflict with Kaido goes, Zoro has a much better case.
If Kaido defeats Yamato and we have Marco and a recovered Zoro available to stall him before he recovers, Zoro is the clear favourite for the role.
But like I don't see either Marco or Zoro stalling Kaido until Luffy recovers. Yamato is currently fighting Kaido, and will continue to do so until Luffy's return. Unlike Sanji, Zoro and Law, she does not believe that Luffy can prevail against Kaido in a 1 vs 1:
If she's to become a Strawhat, this is something that will need to change.
I expect Luffy to save Yamato from Kaido when she's at her wits end in the battle (again like he did for Law):
At that point, Yamato will put her faith in Luffy and trust him to defeat Kaido.
We should get a scene like this:
So yeah, Yamato is fighting Kaido until Luffy recovers.
He couldn't do that before heavy players like Zoro and Sanji come, but now that they are there, nothing stops him in doing an underhanded tactic to temporarily keep Marco away from the plot
Perospero was knocked away from the Live Floor and Nekomamushi is on his way to deal with him. I don't see Marco falling to underhanded tactics. Not when there's no one free to backstab him.
or after King gets weakened after a difficult fight due to Marco only being moderately tired, and thus turning into a weakened King vs healed Zoro.
Meh, I'm not going to debate how injured/weakened King will be when he fights Zoro. If Zoro vs King happens, Oda will make it clear to what extent the respective characters are injured.