I don't know, it seems legit, the Zelda game has a legit title if that's what its called and actually I hope they are planning on Super Smash bros U and Super Smash Bros 3D being official titles cause Super Smash Bros for Wii U and Super Smash Bros for 3ds sounds dumb, they should have confirmed those as official titles long time ago, I still call it Super Smash Bros 4, this to me makes it sound legit.
However Mario Kart 8 was already released, unless they're announcing dlc, I see no reason for mentioning that at E3, and hopefully its more than just that Mercedes Benz, I want to see a few characters as dlc, I want Dry Bowser back, I want Diddy back, put Dixie and Kritter in too.
Usually we see a few Mario games announced though, the only thing Mario is Mario Kart 8, I doubt they'd have a E3 with out any Mario games announced, so this is one reason that points to a fake.
I hope those other games aren't what's being planned because Final Fantasy is bad enough let alone Theat Rythym, and don't even get me started with Xeno, that's a topic best not mentioned with me.