We know that Caribou has information on both ancient weapons: Pluton is in Wano, and Shirahoshi is Poseidon. A common theory I see is that Caribou is talking about giving that information to Blackbeard. But what if he actually means Crocodile?
All Crocodile wanted out of Alabasta was to know about Pluton, now someone comes forward who knows where it and Poseidon are? And all of a sudden Crocodile is reintroduced into the story alongside a Yonko WHO VERY MUCH WOULD like to use the ancient weapons (unlike Luffy)? Buggy failing upwards into possession of ancient weapons would be hilarious.
Plus the fact Caribou was actively killing Marines when we were introduced to him. Crocodile has degree of ruthlessness that suits Caribou tendency to kill Marines too. And now we have Crocodile issuing bounties on Marines…quite the coincidence.
And don’t forget, Caribou never explained why he was targeting Luffy. He probably wanted to impress Crocodile by taking out the pirate who originally defeated him.
Honestly I can see Buggy scheming to get the Strawhats into helping to save him from Mihawk and Crocodile’s grasp, dude is all about self-preservation. They arrive in Wano, he sees the Strawhats flag, and immediately gets the info to them that Cross Guild is there doing stuff.
If Crocodile going for Pluton would cause problems, and Luffy would definitely jump in to protect his territory. Gives Zoro and Mihawk a cool stage for their duel, too, along with the opportunity to revisit Zoro’s backstory that we didn’t get.
Not to mention opening up Wano. By the time this stuff happens I would think they had already visited Raftel to get info, making opening Wano up even more important for the end game.