I think its very nonlinear, for every strawhats dream. Seriously think about it, they all can't happen at the same time:
- Luffy: at Laugh Tale, before/during/after the Final War.
- Zoro: defeating Mihawk, whenever that happens
- Nami: Literally impossible within the confines of the story, must be a timeskip dream
- Usopp: May or may not be achieved by some major event where he defines his dream himself by being brave
- Sanji: all blue can be found whenever but highly doubt it happens at the same time as Luffy or Zoro's
- Chopper: Like Nami, can't happen at all during the main story
- Robin: will happen right before Luffy becomes PK/finds One Piece
- Franky: Refer to Robin's and Luffy's. Around the same time.
- Brook: Post, whenever he's able to see Laboon
- Jinbe: post/final war. Whenever FI gets destroyed and his people can move to the surface.
All very different. All impossible to determine exactly when, let alone remotely being close to each other in accomplishments