List of Characters by Series:

Mario Series: Mario, Luigi, Peach, Bowser, Rosalina

DK Series: Donkey Kong, Diddy & Dixie

Zelda Series: Link, Princess Zelda/Sheik, Toon Link, Toon Zelda/Tetra, Ganondorf

Metroid Series: Samus, Ridley, (ZSS's status is unknown)

Kirby Series: Kirby, Meta Knight, King Dedede

Kid Icarus Series: Pit, Palutena, Hades

Pokemon series: Pikachu, Kanto Trainer (Pokemon Master with Squirtle, Ivysaur and Charizard), Kalos Trainer (Pokemon Trainer with Greninja, Quilladin, and Fennekin), Jigglypuff, Mewtwo (Lucario cut)

Fire Emblem series: Marth, Chrom, (Ike Cut)

Star Fox Series: Fox, Wolf, (Falco Cut)

Earthbound Series: Ness, Lucas

3rd Party: Sonic, Mega Man, Pac-Man, (Snake Cut)

64 Vets: Yoshi, Captain Falcon

Melee Vets: Ice Climbers, Mr. G&W

Brawl Vets: Olimar, ROB, Wario

Newcomer series: Waluigi, Shulk, Mii, Wii Fit Trainer, Little Mac, Villager, Takamaru

Stages by Series

Mario:
WiiU - Mario Circuit, Hands-On Hall

Zelda:
WiiU - Temple (Melee)

Metroid:
3DS - Research Station

Stage Notes: Vorash replaces Ridley much like Alfonso does.

Kirby:
WiiU - Dream Lands, Castle Dedede
3DS - Lollipop Land, Green Greens

Kid Icarus:
WiiU - Underworld

Stage Notes: Underworld is a more vertical stage lined by pillars

Pokemon:
WiiU - Pokemon Stadium, Main Street Colosseum, Pokepark
3DS - Indigo Plateau, Tower of Mastery

Stage Notes: Pokepark has no gimmicks, but is very colorful with Pokemon running around everywhere.

Fire Emblem:
WiiU - Castle Delbray

Earthbound:
WiiU - revamped Onett
3DS - Thunder Tower

3rd Party:
Sonic - Frozen Factory Zone (3DS)
Notes: Has a lot of gears running around, but not much else
Megaman - Pixelated B&W Wily's Castle (3DS)
Pacman - Classic Game (WiiU) / Pac-Attack (3DS)

Melee Series:
Notes: No new Flat Zone, the originals split between the versions as far as he knows.

Newcomer Series:
Xenoblade - Raguel Bridge (WiiU) / Landing Site (3DS)
Takamaru - Shimazu Castle (WiiU) / Forgotten Courtyard (3DS)
Notes: Smashville is said to be one stage, but he doesn't know how it works.

Character Info:

Diddy & Dixie each have a unique moveset, and like in the series, one waits in the background till swapped in.

Zelda's Down+B functions the same, transforming her into Sheik.

Toon Zelda is the one presumably with the Phantom as he hasn't seen it amongst the Assist Trophies he knows about.

Ganondorf's Brawl design is merely upgraded, moveset unknown.

Ridley is a big slow fighter, his design is a mixture of Prime, Retro, and Other M.

Wolf, Ness, and Falcon have their Brawl design updated.

Ike and Lucario’s moves have been shifted to other characters probably to Chrom and Mewtwo respectively.

Waluigi represents the Sports and Party franchise.

Takamaru is made realistic, minimalized purple and now darker, jacket is more a red plate of armor, purple belt, tapered pants. Personally thinks he looks around 25-30 with hair being very dark purple-blue. Not sure why he has a new outfit of light armor.

Little Mac will be taking his appearance from Punch-Out (Wii).

Apparently Aside from Wario, only a few actually have alternate outfits, most have color swaps that closely resemble other outfits.
Misc Info:

Shulk will be revealed on the 30th as playable on account of X being shown as Xenoblade 2, as part of a big media event.

Customization exists on a mechanical level, but no details.

The Wii U version will use special NFC trading cards featuring fighters, locales, and assist trophies for fun mini-games. The Wii U version has some GamePad mini-games, while the 3DS version has some AR functionality using the same cards.

It is very possible that more characters will be added, but he very confident in his "prediction" at the current time. He has no idea what Sakurai might want to implement in the future.

Each character gets a short CG movie. Newcomers get longer ones.

All third party characters, Hades, Palutena, Takamaru, Mewtwo, and others are unlockable, but only the aforementioned for sure.

As far as stages go, he doesn't have a list, just what he happened to see, but he thinks about 10 returning stages per version. Every franchise represented by a character will have a unique stage on each version. Also, most unrepresented stages will be Smash originals.

My Music is back.

Collectibles now include Miiverse Stamps, of the more prominent characters.

Trophy information is sketchy, he didn't get details there.

Fairly confident DLC won't be included, but as stated, not privy to development.

"Story Mode" on both versions with original maps. Enemies and Bosses will be mostly Nintendo ones. The mode just lacks cutscenes. Apparently the boss order changes every run.

Bosses: WiiU - Dino Pirahna, King Hippo, Master Hand / 3DS - Great Reaper, Master Hand

Assist Trophies are the same across versions, like items and fighters. Stages and modes will be the only difference.

Assist Trophies: Isabelle, Elite Beat Agents, Duck Hunt Pup, MGS rep, Ashley (Confirmed), Bubbles, Dominic, Dr. Kawashima, Lucina, Ms. Pac-Man, Proto Man, T-Rex, Zip, S. Goroh (Returning), Kat & Ana (Returning), Lyndis (Returning), Dominic, doesn't know all the ATs, (Excitebike, Infantry, Helirin, Gray Fox, and Saki cut)

AT Notes: Dominic closes the curtains for a second and screws with the costumes, giving all fighters one of their alt colors/

Pokeball: Abomasnow, Bellossom, Binacle, Bonsly, Celebi, Chikorita, Deoxys, Dialga, Electrode, Entei, Genesect, Gogoat, Goldeen, Goodra, Groudon, Gulpin, Hawlucha, Ho-Oh, Jirachi, Klefki, Kyogre, Kyurem Latias, Latios, Lucario, Lugia, Manaphy, Meowth, Mew, Moltres Munchlax, Oshawott, Palkia, Reshiram, Snivy, Snorlax, Suicune, Tepig, Togepi, Victini, Weavile, Wobbuffet, Yveltal, Xerneas, Zekrom, Zoroark

Pokeball Notes: Zoroark transforms into one of the players and attacks, can be knocked out. / Victini floats to the center, does a peace sign and takes off, with a trail of fire that expands on contact with a surface. / Genesect makes a lot of computerized noise and attacks with beams of various elements at random before folding like origami and vanishing. / Xerneas releases a gorgeous bang of colored light that pushes players away. / Klefki floats around dropping a collectible per player. / Lucario runs on a set path with a blue glow around him, hitting all enemies in his path.