Dixie Kong:
Chance 60%
Want 25%
If anything, Dixie's best shot in my eyes is as an echo, which is really an up in the air guess as to how many more we'll receive. I don't know too much about her in terms of history, but I do know she has a few things different about her enough to the point that it is a possibility that Sakurai could decide to make her a semi-clone of Diddy, a-la the recent edition of Isabelle, but I think her best shot is still as an echo at this late stage of the game. If she were implemented, it would be very awesome to see the DK Country trio and their main rival all together in this one Smash game, and I would at least like to see her get the Chrom treatment and have a few special moves that an echo wouldn't normally have.
Shantae:
Chance 65%
Want 100%
I'm a huge advocate for Shantae. Her quirky nature and buoyant outlook on life is something I love in a character, so it's no wonder once I was exposed to the series it skyrocketed to the top of my most wanted list. There are a lot of arguments against her pertaining to Shovel Knight's inclusion as an Assist Trophy, but I see that as more of a boost for her chances than anything. Sakurai has stated that one of the key things he looks for when developing a character is personality and expressiveness, which is difficult to emulate properly on a faceless and voiceless character like Shovel Knight. On the other hand, Shantae is the epitome of expressiveness and personality, where she not only has voice acting but a bright design along with some vibrant animations that lend to her character. It's also worth noting Sakurai would have no issue developing a move set for her due to her overabundance of powerups, transformations, and abilities she has in her games.
We know she had ballot support at the very least, as some of the fan polls online have shown. Wayforward, the series' developer, had a major campaign going back in the ballot period as well along with a new entry in the series brewing at the time, so it's fair to assume she had a good amount of attention and relevancy at the time of the ballot. Also, something I think a lot of people write off is the fact that Shantae's appearances in major relevant indie titles have tapered out in recent years during the development of Smash Ultimate to where she hasn't appeared in any fighting game crossovers whatsoever despite Shovel Knight clearly having no issue appearing in these titles even though he was an assist trophy in Smash Ultimate. Now it may be easy to just write this off as an executive decision by Wayforward, I beg to differ. Wayforward is the type of developer that values their fans more than anything in the world. The whole reason they even began a social media campaign for Shantae's inclusion was because they received messages saying that their fans wanted Shantae in the game. Not only that, but they've consistently time and time again been vocal about answering questions, sharing fan art, and even providing fans with free DLC for their game that nobody asked for as a thank you. If fans wanted Shantae in Rivals of Aether, Blade Strangers, or Indie Pogo, there is no doubt in my mind that they would have given permission in a heartbeat. The fact that they have not yet is odd at the very least. This isn't the only odd thing they've done recently though, as they've also been eerily silent on saying anything themselves about Shantae and Smash Brothers in the same sentence. They will retweet fan art that mentions it, but they will never say a single word about the topic themselves. It is honestly one of the most out of character things a vocal company like Wayforward could do, and I believe it points towards an NDA and a good chance of Shantae being barred from appearing as playable in these other indie fighters as well, being that she has never been in a fighting game before.
As such, I believe Shantae has a fair shot of appearing as a playable character in this game. There is a lot against her at this point, and most people who aren't a part of the Shantae support groups are either unaware of this evidence or have completely written off any chance of an indie being included other than Shovel Knight. Ultimately it all comes down to Sakurai, but I believe that Shantae has had the best chance out of any indie character that could have been viable for Smash this whole time, and with the character reveals winding down I am certain that she is either playable or an assist trophy.