I'm sorry I can't prove this.
The information I have is that this videos and screens are all ESRB material, that was in fact all videos sent from Nintendo.
I may be behind in information regards this, so don't take my word as final.
Correct. There isn't a 'game floating around' out there, that was never part of what's going on. Let's look at this logically.
This is just footage of a long video that is sent to the ESRB for them to evaluate what the game should be rated. There is no game, it's just a video of gameplay footage. With that in mind...
-All-Star Mode being locked doesn't necessarily mean anything because the game footage doesn't necessarily go in any sequential order. In the leak video that shows Shulk victory screen, it goes right into footage of Yoshi doing the sand-bag challenge. It just goes in a seemingly random order.
-The ESRB needs footage of any "questionable" material. Wouldn't Dixie and Impa need to be shown in some capacity if they were playable? I mean they aren't the most sextacular of characters, but...
-Why would the ESRB receive an incomplete roster if they need to evaluate the whole game?
-How would a leaker know if they 'still have things left to unlock'? They aren't actually playing the game, they have no idea how much content there is.
-On that note, if there IS something in the footage that indicate that there are other characters playable, why wouldn't they include that in their giant image dump?
So I think this is what we're getting.