@Polygon:
You do realize you can't ride on that little pony forever, don't you? Once it becomes apparent she's not on the ship you're done for. More than likely it'll become apparent she's not on the ship next chapter. Either way you don't have much time left. Unless Oda decides not to show the SH next chapter, you have until next Wednesday.
I'm "convinced" a former boss character is to be their partner, prior to the new world… Which means, a limited number of so and so's could fit that role.
Granted the validity of the quote, she's one of the few to accept that role.
I'm more so convinced that there will be "two" more Strawhats to come, disappointed a little that it won't be characters that "share" the similar time frame of the journey, like the current cast, but that's nothing.
Given that the "chances" a female character will join seem half and half, I'd think it's more likely a lady would be it.
Considering that Perona has enough space to write anything about, and a solid character build that lets Oda use her enough to establish such events... She's the most flexible in terms of "strawhat-esque" story development.
Aside from all the other characters in the manga, she's the ONLY character that stands a chance, up to this point, concerning a revealed character. Jinbei honestly isn't likely to join-- he's not likely at all.