Oda Foreshadow Vivi being the 10th Straw Hat

I have a theory that Vivi will be the next Straw Hat member, or I would say she will now sail with them. Why?

In the end of the Wano arc, Luffy rejected the ancient weapon Pluton. Obviously, Pluton will be operated or controlled by someone from Wano. That means, somehow later on the story, Momo or Yamato with their own crew will join the Straw Hats with Pluton. If Yamato will be an official member, her role is to guide Momo with Pluton.

We know that Jimbei is the latest member now, who is a fishman. His role will be a guide to the ancient weapon Poseidon, of course in Luffy's behalf (because Luffy is dumb. Haha!).

Then, here comes the next Straw Hat, Vivi. Remember when the straw hats part ways with Vivi? They marked their arms "X", this may be a foreshadowing with Vivi being the 10th Straw Hat because X is the roman numeral for 10. I also believe Alabasta know about Uranus, or somehow they know how it works. It will be the first ancient weapon to be unleashed in a fight or war with Vivi as its operator or controller. Vivi left Alabasta with someone she can trust to lead the country. As of now, we aren't sure if King Cobra really died. Bonnie and Urugue are the only pirates from the worst generation who were not involved in the story yet, so maybe Bonnie had something with it. Vivi also knew Brogy and Dorry, we expect her to meet the straw hats on Elbaf.

Every Straw Hat have their own purpose in the crew. Luffy as Captain. Zoro as the right hand fighter while Sanji as the left hand not just the cook. Robin as the reader of the poneglyph not just the archeologist. Nami as the navigator and the captain in the sea. Chopper as the doctor. Ussop as the grand fleet captain and the sniper. Frankie as the shipwright and has the counter plan against Pluton (which he may use if Pluton goes against them). As I've said earlier, Jimbei will guide poseidon and guide Thousand Sunny through the helm.

I'm missing Brook's other purpose aside from being the musician, I feel that he has some role untold yet. His character is missing some role in the ship. And if Vivi joins, she should also have a 2nd role, maybe a dancer?

So that's my theory, I can't back it up with some clues from the manga or anime. We can discuss things if you can corelate this with some Oda's foreshadowing.