When it comes to buggy, crocodile, and the rest of the crew them all previously having dreams of the one piece and giving up on it are pretty obvious
Us seeing this chapter that the opportunity buggy was given reignited his drive and ambition as a true pirate. Him by the end of it helping bring back the wholes crew passion
Crocodile also had dreams of finding the one piece as we saw in the baroque works cover story
The only current odd one out being mihawk so far but what if like the rest of them he also once shared that ambition. Hes at the very least like the rest of them going to take part in it now cause it isn't like he's just going to leave cross guild now.
If he was once after the one piece just the rest of them what do you think killed his ambition and made him stop?
Gecko moria joining would also be even more fitting because he's another character that was after the one piece but gave up. Maybe cross guild will be made up of members that previously gave up on their dreams of finding the one piece with buggy unironically bringing that passion back