3(One Piece)

An Au where Luffy never left Dawn but his crew still found their way to him.

An example, Luffy works at Makino's bar/restaurant and Coby ends up in Dawn after gaining courage to run away from Alvina. Luffy finds Coby and basically takes him in and listens to Coby's story before informing him that he could stay with him until Garp came for a visit and then he could ask him to join the marines.

Zoro deals with Helmeppo's father alone and a bit later but once he did and saved the town from his oppressive rule, he got lost and ended up in Dawn where he joined Luffy and Coby but unlike Coby he ended up staying for longer and when he left, he somehow always found his way back to Dawn easily.

And the others end up finding their way to Dawn and meeting Luffy who tells them to follow their dreams(not sure how Brook would end up in Dawn...maybe someone with a Devil Fruit that could create portals fights Brook and he falls in one which leads him to Dawn?).

And maybe, at some point when they have all met each other, they decided to ask Luffy what is dream was and once they heard it, they promise to help reach it.

Anything else, is up to the writer.