Ridley is confirmed as a boss in the game.

Bayonetta and Shulk mostly and both have a good chance.
Just out of curiosity, why do u want a character like Dixie ? There is absolutely no possible moveset tht coul differ from Diddie's

Returning:
Jiggylipuff

Third party:
geno

The cast is great to me, I don't have any particular character requests left -- nothing realistic, anyway. Now my hopes are mainly for stages. Xenoblade stage, W101 stage, stuff like that. I don't particularly care about playable Shulk* or Wonder Red or anything.

(*I say this now, but if and when Shulk is confirmed, I'm sure I'll think he's the coolest shit, just like my reaction to every other newcomer so far.)

No he is not. He is neither confirmed or deconfirmed. I think his shadow is just a tease for him playable although he COULD be a stage boss as easily! I will quote a certain user here: (VERY LONG but you should at least read the  Section 2 where the footage is analysed.).

"""""""""""1. Wasn't Ridley deconfirmed?

No

First of all, it's "disconfirmed", it drives me nuts when people use deconfirmed, as that would mean the character was confirmed, but deconfirmed later.

Secondly, Sakurai didn't disconfirm Ridley in any way shape or form. When Sakurai disconfirms characters, he makes sure to specify that these characters willNOT be playable, or explicitly showing them in a roll where they CANNOT . Characters including:
1. Skull Kid
2. Ashley
3. Waluigi
4. Chrom
5. Every Assist Trophy and Pokeball in the Direct
6. Every Assist Trophy and Pokeball ever 

He even went out of his way to disconfirm Brittany from Pikmin 3 when showing her trophy. He specifically went out of his way to state that this rather insignificant character would not be playable in Smash Bros. THAT is a disconfirmation people.

"But Kalimdori, Sakurai has never shown a character before they were announced! He even said that characters are officially announced on the website, therefore any character that isn't announced HAS to be deconfirmed!"

Oh my gosh you are absolutely right! And by that logic:
T. Link = Deconfirmed
Miis = Deconfirmed
Palutena = Deconfirmed
Game and Watch = Deconfirmed

Not only is that statement naive, it's downright false, as I just showed. A character is not disconfirmed until Sakurai says so, or it is shown in such a way it cannot be playable. This is why Ridley is not disconfirmed, and why several of the characters people think are "Deconfirmed" are not (Zoroark, Rayman, Wonder Red, Dark Pit, etc.)
2. Ridley is a boss, not a character!

I'm going to split this into 2 sections: Size and behavior

Size: To put it bluntly, outside of his NES appearance, Ridley is the smallest he's ever been in this game, nearly half the size he was in Brawl. If you want to know how I came to this conclusion, please visit the second post of the Ridley thread, I'm not going to copy and paste that over here. (Because then this post would be too big) 

Behavior: I'm seeing people claiming that we "Don't know how bosses work and move" in this game, and therefore, Ridley's behavior in the Direct isn't something that can be shown as evidence to his playability. Which I would agree would be the case, if we didn't already have a boss fight to base it off of!

To those of you who never touched Subspace Emissary, never played Smash before now, or have a very short memory span, Ridley was a boss before in Smash Bros. Twice. Both of these fights had an active, fast Ridley that was constantly attacking the player. In this iteration, we have a Ridley that casually flies in from the right at a slow speed, hovers in midair for a few seconds (Possibly with a Pikachu in his hands, but that's not a certainty), and casually flies off to the left, only to immediately come back ascending to a higher altitude. If this is a boss fight, it's downright boring, especially compared to his Brawl battles.

Not only that, but Ridley's animations in this are incredibly choppy, his speed is extremely slow compared to his previous battles, he is moving directly across the axis that players move across, even when gaining altitude, and goes a full 12 seconds without A) Attacking, or B) Assuming he did grab Pikachu, did absolutely nothing with him. So if this is a boss, it is a slow boss that does not attack and possibly grabs people without doing anything.

Or it's someone controlling a character.

3. Sakurai is hyping him up as a boss!

This excuse. This excuse. This excuse drives me up the wall more then any other one. The claims that Ridley is to big or to overpowered or wouldn't have a moveset are so idiotic that it baffles me how people still think they are viable, and I'm not going to waste my time trying to prove them wrong. (Yes, if you believe either of those arguments I just called you an idiot #sorrynotsorry)

If Sakurai is just hyping up Ridley as a stage boss, he is taking one of the most requested characters to be in this game and slapping him into a gimmick of a feature that has always been present in Smash Bros. This would be akin to hyping up Mewtwo as a Master Ball Pokemon.

In conclusion:
If Ridley is a boss, he is a poorly designed, diminutive boss that has been deliberately hidden and hyped up for no apparent reason. If he is a character, Sakurai has been keeping him a secret for a future reveal, and is creating controversy around him to build hype, similarly to what he did with Palutena. As such, I give Ridley:

Chance: 99%
With a 1% chance that Sakurai is either an idiot or deliberately being a douche to Ridley fans. Both of which I don't believe are true. There is no logical explanation for Sakurai's behavior if Ridley is just a boss."""""""""""""""""""""""

Why not? lol. She is cool and yes there is a chance she could be a semi clone ala Luigi & Mario.

From the top of my head I can think of....

Hair-licotper - like in her game uses her hair to go up.Bubblegum gun - sticks opponents to place for a short time (or something).A bunch of hair attacks to combine with kicks/punches.Use that crossbow? (no crossbows in Smash yet! :P)

Summoning the jungle friends as the Final Smash perhaps. She CAN be different! ;). 

double doubles.

Shulk and Ganondorf.

Did you see the Smash Bros. Direct?

He talks about how the Yellow Devil is a stage boss and then you see the Metroid stage and the shadow of Ridley and he says other boss characters will be in the game with the text "Other boss characters appearances"...

Most wanted is fine, but Bayo doesn't have a good chance.

That said, What makes you think Dixie would be a clone? If Sakurai can make Ness/Lucas, Fox/Wolf, Mario/Luigi, Be different im sure Dixie can be too. Dixie has her hair which can easily make Dixie/Diddy much more different than the pairs i listed before :)