CoC is different though, it depends on willpower, and it can't be trained, which I assume extends to fights as well.
I'm not sure if that's possible unless they choose a direction/area, as there'd be no way to tell who knocked out the most enemy.
Is that confirmed? Motobaro calmed down, but he was still conscious, or am I recalling that incorrectly? But yeah, as you said, traumatic and dangerous situations likely awaken haki, and for Luffy, Marguerite's possible death was dangerous enough for him. Ace protected Dadan while Luffy protected Marguerite and Ace. I think Ace and Luffy unconsciously used their CoC to protect others while Doflamingo did it to protect himself? I'm not sure if that says anything though.
I don't think it'd have done anything against the Pacifista, as they seem to be emotionless robots, though I think Whitebeard had the strength with his CoC to do something to them.
Sanji and Zoro's goals are also to help Luffy become the Pirate King, and Zoro was willing to give up on his dream of being the World's Strongest Swordsman to ensure Kuma wouldn't kill and take Luffy. They both likely do need CoC given the level and amount of enemies they'll be up against. It's also not just because of parallels between the two crews, but because it'd be cool to see Zoro and Sanji have that kind of power, especially given the challenges that lie ahead. I'm thinking Raftel will be difficult, as well as the aftermath.
Yep, and it helps that Zoro's shown criteria for being able to use CoC, like scaring Monet shitless.