I don't think "the major spots that the leaker messed up if fake are the spots that are always covered up by characters in the available mural" is a lot of assumptions.
Here's a real example of Occam's Razer.
- First we need to believe the leaker is Eric, and not someone impersonating him, he's come forth and we need to assume he's lying as well.
- Then we need to assume Marina is lying about working on Ultimate.
- If they aren't lying, we have to assume that the Eric (or the leaker) has to be working at ACP as well.
- In order to assume that ACP or Marina is involved we have to assume they're working on the Grinch promo material when none have confirmed it, and none have any connections to Universal or Nintendo it seems.
- We also have to assume that the leaker has no connections to the Chad Ganondorf leak and it's all a coincidence, if he really was just a printer at ACP how would he even possibly know what characters were cut?
You're stretching it too far.
A simple explanation for how the leak could be legitimate is as simple as:
1. The Grinch leak is unrelated to all other leaks because it's real (Nintendo already got their feathers ruffled over a leak, this was confirmed about a month back so a legitimate leak has indeed happened already), this includes the Chadnondorf leak (likely the leak Nintendo is ruffled over as it had insider development info), and Papageno's source.
2. The Grinch leak is simply a result of someone working on Smash content for a printing company (all of these have evidence) called APC, accidentally leaking the banner because he was overworked and didn't realize it was confidential. Note, it had to be someone called Eric Bricard as the Snapchat profile has that name.
Now provide me with all the countless assumptions you need to make to assume the leak is fake. Go on.