Sora, Donald, and Goofy
Sora and the gang return for more action in the sequal to Chain of Memories. After the events of Castle Oblivion, Sora awakens to begin his adventure for KH2. Somewhere in the game, Sora gets his new clothes. Donald and Goofy, too, come back in this sequal and tag along with Sora for more adventures.
Kairi & Selphie
Kairi returns to KH2 on Destiny Islands. Don't get confused, DI is plural, meaning more than one island. We see her on another island in the chain in KH2. She is seen with Selphie in the Jump Festa '04 trailer.
Selphie returns right alongside her, and likely, the other Destiny Islands Final Fantasy characters, too.
Riku
Riku still isn't confirmed for KH2, but we know he's going to be in it.
*CoM Spoilers*
Riku dons an Organization suit in CoM, which symbolizes that he is light and dark now, and he will likely don it in KH2. He is probally traveling with Mickey in KH2, who appears in Twilight Town and I wouldn't be suprised if Riku shows up right along with him.
BHK(Blonde-Haired Kid)/Blonde
We still don't know crap about Blonde, at least now we've seen his face. It seems he is Sora's other self, the person in the world in-between who has a connection with him at the heart. KH2s theme is "connections of heart" afterall. He lives in Twilight Town, and goes through his own awakening/dive to the heart in KH2, and wields the Oathkeeper and the Oblivion. But he does live in the world in-between, so they are likely not Sora's keychains. More mystery was added to this character at E3 2005. He is seen with a Kingdom Key keyblade only attacking DiZ in a memory pod room from CoM.
Namine
Namine is the witch in Chain of Memories who tinkered with Sora's mind. She shows up in Twilight Town in KH2 and is seen talking with Blonde. Who know's what the connection is there, maybe she is Blonde's Kairi, or his sister, or just a friend, who knows. Either way, CoM wasn't the last we saw of her. We know Sora won't remember her, but memories are not lost, only forgotten...
Pete
Pete is likely the character who takes Maleficient's role in KH2, the evil person who seems to be playing everyone. Not much is known about his role, but the fact that he's seen trying to do stuff with both Hades and Jafar can only mean he has a maleficient like role. And we fight him in the Underworld... maybe we fight him a lot throughout the game?
The Organization
This is the 13th Order (The Organization), a group of NEOs (body and soul with no heart) that are neither light nor dark. Their intentions with Sora and Riku in CoM need not be spoiled here, but it seems like the events of CoM will not affect their KH2 intentions, whatever they may be. There are at 13 members, led by the Superior, it is unknown if the Superior is part of the number count or not. They are concerned with matters of the heart, which is likely to play a role in what they are doing in KH2. Xaldin has dropped the hint that they want to open up Kingdom Hearts and get their hearts back.
Axel
Axel is a member of The Organization who uses wind/fire wheel weapons and can cast a spell that causes a ring of fire to appear. He appears in both CoM and KH2. He is Organization member # 8. He is loyal to the Organization to the end, he will not permit the breaking of the rules that the Organization is supposed to follow, and will even kill traitors. He is slightly hot headed, but at the same time, he knows when, where, and how to act. He is the only one from CoM who makes it into the sequal, but Sora will not remember him. The question is, will Sora's memories of him ever resurface? Does it even matter?
Xaldin
Xaldin is the 13th Order member that shows up for the first time in Beast's Castle. Using 6 Naginatas which he can use without even touching him, Xaldin will be a force to be reckoned with. He hints at wanting to kidnap Belle to help open up Kingdom Hearts.
Demix
DMX is a brand new Order member who has zero information at this point besides his name. He is carrying a very big weapon which appears to have 3 strings on it, but they could just be lines.
Enigmatic Man (Fan Name)
Not much is known about him, in FM, he states he is a "mere shell". Read his section in the Final Mix area for more. It is quite possible he is the Org. member who appears at Fabled Countryside, they both stand the same way.
Nomura: The man in the center of the image with the 5 hooded men standing side by side is the character Sora fought in "Final Mix". And the man in robe who Sora is attacking is the same person who is talking to the character with red clothes. In fact, this is something even the staff doesn't know (laughs).
Nomura: The man in the center of the image with the 5 hooded men standing side by side is the character Sora fought in "Final Mix"...
Organization Member With No Name
(Continued from above Nomura interview)...And the man in robe who Sora is attacking is the same person who is talking to the character with red clothes. In fact, this is something even the staff don't know (laughs).
Nothing to say... we don't know anything about him! My prediction? It's Axel, Sora is going to jump at him to attack, but suddenly he will have an unexplainable feeling in his heart. Then again it could be Riku... or a new member... or EM.
DiZ
It is unknown whether he is a member of the Org. or not. It's possible that he's actually the Superior of the Organization. Anyways, he like Riku, follows Twilight, both light and dark (or neither). He is likely Ansem's body and soul, which he cast off long ago (read Ansem Report 13). His intentions differ from the Organization, which will lilely be a vital plot point to Kingdom hearts 2.
Mickey
Mickey has donned an Organization jacket, along with Riku. Likely it symbolizes that they are both neither light nor dark, but it could mean more. His intentions in KH2 are still unknown, and CoM didn't really give us anything to go on. But, we can assume that Riku is with Mickey now after CoM. He shows up in KH2 at Twilight Town, where he saves Sora from a Nobody attack.
Beast
Yep, the Beast is back. The Organization member is obviously manipulating him to attack Sora, but, there is probally more than that going on... and note, in the E3 trailer, Beast is in your party, so i'm guessing that Beast's world is going to be split into two series of events, one for Beast attacking you, and one for going after the Organization member/sealing the world. I guess we'll see. The Organization member says "That Woman is going to deprive you from everything/take everything away from you." & "Who could ever love a beast like you?" Obviously, he is using the rose and his feelings of Belle against him and forcing him to do things.
Belle
Belle returns in KH2... and Xaldin wants to kidnap her for use of the 13th Order. Yea, she's having a lot of fun in these games...
Mrs. Potts, Lumiere, Cogsworth & Chip
Nothing special with them, just characters you come across in the Beauty & The Beast world.
Hades, Pain & Panic
Hades returns in KH2, this time we see him in his natural habitat, the Underworld. He summons Auron to kill Sora, Auron goes after Hades, Hades calls Cerberus... you know how it goes. He is also holding an underworld Colisuem tournament, which should be quite interesting. He's just back doing more villainous things, plain and simple.
Hercules
Sora says "Being a hero-in-training is busy work!" to Hercules, so it's just the same 'ol Hercules. His world should be even better than ever, Nomura already said the colisuem would be way better, and now you can go to the Underworld (which has it's own Colisuem) and quite possibly Mt. Thebes and Greece.
Meg
She is Hercules girlfriend. He gives up his chance to be a god to be with her.
Auron
Hades says to Auron "Well then, sinner/criminal. Let's carry out our contract right now, shall we?." So, he is working with Hades in a way similiar to how Cloud did in KH1. But... rigth after Hades says that, Auron gets into attack position... what's going on there? But, since Auron is in The Underworld, we can assume he is dead like he was in FFX. He probally died at HB when the heartless came, they will have some reason how he died but didn't lose his heart or something... I guess we will see. Anyways, he is being hired by Hades to defeat Sora, he doesn't agree with this (the reason why he get into battle stance) and you fight along side him against Hades, and then in a battle with Cerebrus and Hades (might not be both at same time though.) He is a party member int he underworld.
Mulan & Mushu
Mulan's role in KH2 likely follows the story of the movie. She takes the place of her father, and dresses up like a man to fight to defeat the Huns. Someone email me with a better description to use.
We also get to see Mushu in his world this time around, since it was restored at the end of KH1.
Ling, Li-Shang, Yao, & Chien-Po
These are the various characters of the Mulan world, Captain Li-Shang is the only one you should care about as he is well, the captain.
Shan-Yu
Shan-Yu is the villain of the Mulan world.
Aladdin
Alladin returns in KH2, it is unclear which storyline Agrabah follows in KH2, according to some people one of the caves is from the 3rd movie, along with the jewel Abu has, but also, with Jafar's black lamp in Pete's hands it seems that it would follow the Return of Jafar. Maybe both the King of Thieves AND Return of the Jafar will make up Agrabah in KH2.
Jack Skellington
Jack returns for more Halloweentown fun, and of course you can tell by looking at the pic, we're in for some Chrismastown fun. Yes, that's CT, look at the buildings, that's certainly not Halloweentown and that's snow you see there. Anyways, it appears that Jack is trying to bring Christmas to Halloweentown, I can't remember the story of The Nightmare Before Christmas that well.
Jack Sparrow
Captain Jack Sparrow joins up with Sora to track down Elizabeth Swann and his old ship, the Black Pearl. It is not yet known whether or not Johnny Depp will be his Voice Actor, but I hope he will.
Elizabeth Swann