MG I've been following this forum forever but just created an account because of this theory. Just want to say that I support this theory so much.
All of the members of the Strawhats are somewhat out of their own league.
Monster Trio are obviously superhuman strength.
Nami is a navigator/cartographer genius and Usopp is multi-talented super eyesight hereditary - both are superb compare to ordinary human.
Robin is a paramecia user but is also a poneglyph reader - multiple times a threat of a normal paramecia.
Chopper is a Zoan of human intelligence and is the only Zoan in the series with 7 forms of transformation - superior compared to any other Zoan users.
Franky is a shipwright/weapon-making genius and is a cyborg at the same time - SUPERRR.
Brook is a musician/paramecia devil fruit user BUT he comes in bones - most unique character design we've seen in OP.
It would make perfect sense to me if Monet is to join this bunch of notorious because Monet is not very normal herself. She is a logia user but comes in a somewhat hybrid Zoan form, which distinguishes her from any other of the same type.
One other thing is that like Nami and Robin, Monet made her appearance very early when they enter a new sea. And like the former two, she has had direct interaction with the beast Zoro. I believe that gaining trust from Zoro is the final stage when a female member wants to join Strawhats. Zoro never trusted Nami before Arlong Park. And he was also the only person against Robin joining. Therefore a female character that directly encountered Zoro would challenge his belief in her as a comrade much more than any other candidates we're looking at right now.
I also read the theory of how Nami and Robin had a connection and Nami foreshadowed Robin etc. I agree 100% that this is a foreshadow of Robin.