Here's the thing, the 3DS image posted just now could turn out being fake but that wouldn't mean the Wii U ones are also fake. The 3DS image posted could be posted by somebody else who is deciding to mess with everyone with his/her Photoshop skills. We don't know if this is the case though because we can't match the tripcodes.
The ESRB leak had similar stuff going on (though not an outright CSS on a different console with the leaked characters on it).
All I'm saying is, the 3DS image is more likely to be fake because of that but that wouldn't mean the Wii U ones are also fake. The only way the Wii U images could be proven fake is if Mewtwo is revealed with a completely different render or Nintendo reveals their full DLC plans for Smash 4 and Rayman is not confirmed as part of it. Reaching for "potential inaccuracies" is not going to get us anywhere lol (as the ESRB leak should have taught people).
If it can't immediately be proven fake with existing renders out there or signs of Photoshop editing, it's up to the individual to decide on what they believe it is in terms of being fake, real, or in the middle.
