So, even if people disagree that the Destiny Islands blade is Kairi's, there's still a big chance that Kairi COULD end up with a keyblade. Not that many people would want that.
That kind of goes without saying, but that's because that thanks to BBS, Tidus, Selphie and Wakka have chances of getting Keyblades, going by Nomura's words about there being as many Keyblades as there are qualified Hearts. However, between saying she could get one and saying she got one from Riku... you get my point :\ there way to go is a long one.
Optional, maybe. But without Donald and Goofy, it just wouldn't be right. They are the main ties to Disney.
And I get the impression that Sora is closer to them than he is to Riku and Kairi at some points.
Well, that has mostly to do with how the story went. I disagree about Riku at the end of the line (KH2 kind of shows that as close as Donald and Goofy might be to Sora, Riku's still 'the best'), and though my views about Kairi are well known (and if they aren't, lol, I need to get out of hiatus properly), it's still their fault for not showing us proper interaction with them - present day one, let alone past one to show why Sora should care at all, if he indeed does.
Sora, Donald and Goofy are a party. They made it a point to develop their friendship through KH1, put it to the test in CoM, and show just how far it got in KH2. I don't think it's really fair saying they're better friends to Sora than Riku and Kairi, in light of Riku and Kairi never getting the 'chance' to really shine - especially not when Riku did shine, just not for as long as Donald and Goofy - simply for plot reasons.
if that happened SRK would just be the new age TAV.
Uh... good morning, that's kind of one of the likely things to happen.