SonicMario
Smash Master
1. Dixie seems more likely simply because of how Donkey Kong's probably going to increase in representation this time around. And while Dixie shouldn't be a complete clone. She'd be easy to base off of Diddy. It's been considered a strong possibility that DK's representation is doubled this time around with K. Rool getting in thanks to strong results in the ballot and a character like Dixie as an extra character. DK is considered the subseries most likely to gain new reps. The mainline Mario series could already be seen as represented well enough already.1. How do we know that Dixie Kong is likelier than Daisy? She has been realtively ignored by Nintendo for years until very recently, in a game that has Cranky Kong and Funky Kong returning. She couldn't even get into Mario Kart Wii whilst Funky did. Sakurai may have considered her as part of Diddy's moveset, but not as a solo character.
2. The Peach alt looking less like Daisy all of the time is one thing, but Daisy got a lot more references in Smash 4 than she did in Brawl. That Mii costume that people champion with K Rool? Daisy was one of the few non Smash characters to get one in the base game. And they were not ripped directly from the Plaza.
3. I am honestly not sure about Captain Toad and Paper Mario making it in. Captain Toad doesn't seem like he could fight and Paper Mario is going to be a third Mario. Oh, and one of the reasons why I think Daisy might have an edge is because she is pretty much one of the only female Mario characters left to add who would make a viable fighter.
2. I don't put too much stake on the Mii Costumes myself. Some costumes are obviously just bonus representation for the series and/or some neat nods to other games especially the costumes that are from 3rd Party games. Though there is certainly some that are indicative of being consolation prizes in doing well in the ballot and/or hints that they're being saved for later. K. Rool's happen to be heavily based on his classic design. Something that hasn't been used for K. Rool in ages. Daisy did get the hair and crown in the base game. But that feels like extra Mario series hats along with Waluigi's as well as the hats for Mario characters that are in the game (Mario and Luigi's hat, Peach's Crown). It's not exactly a full costume either with no option to give your Mii Daisy's dress or Sports attire.
3. Using the argument of a character doesn't seem like they could fight in a series that has included characters like ROB and Wii Fit Trainer is ridiculous. And Captain Toad would certainly have more to pull from then many characters thought unlikely to be fighting. As noted whenever the "Captain Toad can't jump" argument comes about. Either Captain Toad will have the excuse of "He packed lighter" so he can jump (Though still not that high, Toads in games in where they have unique attributes have them with the shortest jump out of them and Mario, Luigi, and Peach but the quickest speed). Or they'll make that fact some sort of gimmick that helps Captain Toad be one of the most unique fighters out of all of them. Game Explain's video was an example of how that could work. I'm not 100% sure that's exactly what they'll do but never underestimate Sakurai's creativity.
As for Paper Mario, if the Mario RPGs get a rep at all it would likely be Paper Mario simply because a 3rd Party Square character (Whether that's an additional Final Fantasy character other then Cloud or someone from Dragon Quest or anybody else Square has to offer that would make for a worthy 3rd party addition) is probably more of a priority then Geno is. Paper Mario still gets games too, granted games that fans of the older games aren't exactly fond of but still new games nonetheless. Dr. Mario was a last minute clone and probably a bit of a nod to fans of Melee. I don't put too much stake of Dr. Mario blocking Paper Mario's way. Albeit I would prefer Dr. Mario to become an alt for regular Mario and Paper Mario to come in as THE 2nd Mario.
Toad/Captain Toad and Paper Mario are both Daisy's and Waluigi's biggest roadblocks for this Smash. Though my personal guess is we either get Toad/Captain Toad or no new Mario characters at all. (And I mean those specifically that would have the mushroom symbol, DK I know kinda counts as Mario but that series is honestly more separate from Mario then either Wario's or Yoshi's games.)