I have a source on the localization team. He says that the character list is final, and characters like Ridley, Chorus Kids, and Dixie will not be in. The only thing 3DS connectivity is used for is eight-player Smash.
The gamepad can be used in a playable boss battle mode - bosses on different stages can be controlled in this way, including Ridley, Metal Face, Yellow Devil, Dry Bowser, and Master Hand.
He could give me some examples of stages:
Bowser's Castle - Based on the original Super Mario Bros. game. The arena is the area where you would face Bowser, but it's given a more modern look like Mushroomy Kingdom. Dry Bowser shows up, and acts as another stage boss. He's larger than Bowser, and can be defeated by either dealing enough damage or pulling the axe that removes the bridge. Players can also fall into the lava pit.
Gaur Plains - This stage is actually different from its 3DS counterpart. It's much bigger, and it actually scrolls around. Metal Face appears on the stage too, acting similarly to the Yellow Devil.
Wii Sports Resort - A traveling stage in the same style as Isle Delfino/Skyloft. Travels around Wuhu Island, stopping at different sporting areas.
Barudo Island - He wasn't really sure as to what this was, but apparently it's like Tortimer Island in that it has a random layout each time you play it. You can even terraform the land by raising and lowering the ground and moving trees around. He says it's pretty chaotic.
He also told me that Hyrule Temple and Rainbow Cruise are back, along with a stage based on Wrecking Crew (he wouldn't provide more info on that one).
The source is a friend of mine, and I know for sure that he's working in the localization process. He could be joking, but he's not someone to lie about stuff like this. I thought I would share anyway.
