My opinion on Chapter 1060's development:
Luffy's dream "reveal"
I don't see this as closing the door any new crewmates. The scene does not carry even a hint of subtext in that direction. There's no finality in it. It doesn't come in the trail of any conversation about the crew itself. It carries no implication that this is a decisive moment. There's not even a hint that this is the final crew.
Heck, even Caribou was there hearing it. Oda made a point in showing his barrel at the corner of the panel after the crew's reactions. He was there, he will bring Luffy's dream to whoever he's selling information.
Also, because the dream wasn't really revealed, the subject can still come up in a multitude of ways in the future. Next crewmate could learn the dream through another crewmate, or by Luffy making the real revelation to us readers, or by having a dream that is similar or complementary that Luffy instantly feels kinship toward him/her.
So no, the "revelation" carries no weight to the next crewmate discussion, in my opinion.
Carrot
This chapter did not end Carrot's chances, and I hate it. I don't think Carrot stowed away, but as long as the story does not clearly reduces the chances to zero, the indefinition will remain.
How can Carrot be in the ship and not have shown herself after days? Simple. She was in the barrel that they put Caribou in. She's now trapped inside his swamp body, and she may be freed at any moment after Caribou escapes. So, as long as Caribou remains in the story, the chance is there. It's ever-diminishing, but, like Luffy's chances of surviving in Marineford, it never reaches zero.
Oh, sounds absurd? Oda has a penchant for the absurd. I don't know if this intentional on his part (I don't think so), but the problem is there all the same.
Bonney
It's of course too early to judge Bonney right now. However, she is sure to be featured a lot and have at least some level of character exploration ahead, so keep your eyes open for any signs of candidacy.
@Shin10-Bukuro said in Next Straw Hat Crewmates (Vol. 9 - Yamato vs. The World):
I think there's something else to take from those sketches you posted: Each Strawhat crewmate had a designated role before they had a finalized design or name.
Indeed, that's another important point.