On another thread, I had a discussion with Zik to determine whether Johnny and Yosaku could return to the main story or not. I figured there were a lot of characters that we haven't heard of for a long time, and that are in the same cases than Johnny and Yosaku. I didn't put characters like Sabo, Moria, the giant we saw in Sabaody… because it's obvious we will see them again.
So, among the characters in the poll, who do you think will return in the main story (multiple choices)?
If you think only some of them will make a cameo appearance, check this option and tell in a post which character will make it.
I think we will see them again. But none will truly return in the main story. If there is a war against the WG, then I think we might see the CP9 or Foxy appearing and helping the Strawhat, but I don't think Oda will use them for another purpose. Concerning Morgan, I think we will see him again near the end being easily defeated by Helmeppo, but that's all. And concerning the others, We will only see their whereabouts at some points of the story, but I don't believe they will play a role in the story.