If this leak is fake, then the guy who made it has to be the craziest person in the world going out of their way to make incredibly boring cardboard cut-out models using promotional material from the upcoming Grinch movie because he's thinking 47 steps ahead and knows that both Bandai-Namco and Universal studios contract the same obscure French marketing company. To this end, he then got himself an office, printed out the name of an employee of said company, and haphazardly half blurred out the name because, once again, he's some kind of super genius beyond the mental capacities of mortal man and he knew that the internet's crack team of cybersleuths would find his red-herring name in seconds.
This absolute Einstein of social engineering also happens to moonlight as an expert artist and after presumably spending hours carefully cutting and pasting characters from the Smash poster, he then went out of his way to produce 7 more drawings of his own with obscure elements like vines for Isaac that hardly anyone would be able to make out, and then, for the fun of it, he saw to making a completely unique drawing of the blank version of Battlefield just because he could. He made sure that this fake roster of his perfectly mirrored one posted on 4chan last month by someone whose first language clearly isn't English because he knew that people would immediately make the connection to the French marketing company that he is pretending produced this image. The fact that 5 new characters lines up with the 5 missing stages from Corocoro was all part of his master plan. He also made sure this coincided with Nintendo renewing relevant trademarks.
The lengths you have to go to believe that this is all an incredibly elaborate leak would make this man one of the most intelligent people to ever walk the Earth. This guy would be more competent than the entire government of Saudi Arabia when it comes to fakery.
I suggest you think about which outcome is more likely.