I'm taking a wait and see approach. There is a lot of things going for it due to the circumstances of the snapchat images around it such as the guy actually being an existing worker for Bamco, the Grinch, the banner not having any obvious flaws (at least so far), and the attention to detail in all areas. However, we also have all of the insiders, whom from what we've seen do know something about this game, all be either pretty skittish in supporting it, or outright denying. It's a really strange scenario where the evidence seems to fit, but the jury won't make the verdict, a case not helped since the latter has knowledge of other evidence that's being withheld.
It definitely will be interesting to see how this evolves, I would be happy if this was real though with this since everything about it is positive to me (Banjo? Mach Rider as a cool Retro Rep? MH and Dixie considered as characters? I'll take it!).