Blackbeard's crew is also a diverse bunch. His more aggressive members like Burgess might be eager to start a fight with Luffy's crew. However, some of the more cunning members could be thinking of ways to use the situation to their advantage. They might try to manipulate Luffy or his crew into making mistakes. And if Blackbeard decides on a certain course of action, his crew would generally follow, but there could be some internal dissent depending on the situation.
It could also be that instead of fighting right away, there's a tense stand - off. Luffy, remembering Ace's past encounters with Blackbeard, would be full of anger and distrust. Blackbeard, on the other hand, might try to taunt Luffy, trying to get him to make a rash move. The situation could escalate slowly as they exchange words, with their crews on edge, waiting for the first sign of action.
Yes. The conflicts between Sanji and Luffy in the manga often stem from complex circumstances and character developments that drive the narrative forward.
Well, in such a fanfiction, Ace might be worried about Luffy. Since Blackbeard is a dangerous character. He could decide to go and find Luffy to protect him. Maybe he'd start looking for Blackbeard too, to make sure he doesn't harm his little brother.