The proper answer to her invitation is being saved for when they do Jinbe's delayed toast. It couldn't be more clear with him telling her to wait on Luffy's answer, both of them randomly being absent from the toast this chapter, and the looming title connection "The Sake I Brewed to Drink With You, Straw Hat Luffy".
1. Throughout this entire arc Yamato fans have been moving the goalposts for when Luffy would accept her. First it was that Luffy would let her in the crew when he defeated Kaido. Then it was that Luffy would accept her when he wakes up. Then it was that Luffy would accept her at the party. Now it's that Luffy will accept her at some unspecified point
It's blatantly obvious that Yamato's desire to join the crew is not being taken seriously by the narrative. That's what I'm getting at here.
2. The part about the poem is blatantly incorrect and is built on nothing but baseless headcanon. Chapter 999’s title was a reference to a Japanese poem written in the 8th century, which goes as follows:
The sake I brewed to drink with you, I drink alone in the field of peace, for I no longer have a friend to drink it with
In the poem, the speaker references their deceased friend, who goes unnamed. The reason why this title was used for chapter 999 is because chapter 999 was about Ace, Yamato's deceased friend. You're trying to make it seem like Chapter 999's and Chapter 1000's titles are referring to Yamato brewing sake for Luffy, even though this completely goes against what the poem was actually about.
It's already set in stone that Luffy will address it and given how glued together they've been since he woke up, it's copium to think he'll just say no. That's probably why you're banking on a last minute Greenbull twist.
Again, whether or not a character joins is up to the author, not the characters they're writing. If Oda decides for Yamato to join, she won't join no matter what. That's just how it is
Jinbe was a side character for almost all of his flashback, has a dream that was never explicitly stated, and a role that was never a problem for the crew.
Jimbei wasn't a side character in his flashback. The whole point of his flashback was to show how he developed the ideals he did by inheriting Tiger's and Otohime's wills. The reason why he's not the main focus until the end is because the entire flashback up until that point was about how Tiger and Otohime affected him and made him into the person he currently is. You're trying to deflect from the fact that Yamato's flashback was incredibly lackluster and told us nothing new that we couldn't already infer.
We have known from the beginning that Jimbi had talents and abilities that no Strawhat has. Him being a helmsman is only an application of the talents we had already seen from him.
In Franky's arc, the primary focus and Luffy's main motivation was Robin. The only trust you see between him and Franky is when he told him to protect Robin. It took until the very end of the arc for Luffy to show any interest in wanting him to join.
And you're forgetting the fact that the story went to great lengths to show Franky genuinely bonding with Robin and Usopp. Yamato hasn't gotten that with any character other than Momo
Right, she spent 2 decades watching the oppressive power Kaido had over Wano yet someone weaker than him will be the one to change her mind on the last minute. A whole week in Wano mainland and her df has yet to be cared for outside of one chapter by Kaido.
Yes. Unironically.
It'll tie into the theme of Luffy bringing the dawn. Wano's borders can't open until Luffy brings the dawn and Yamato can't leave until that happens. So this given Luffy a personal stake in wanting to bring the dawn.