here are random things
1: Skull Kid and Isabelle
2: Chorus Men
3: Ken, Isaac, Shadow
4: Agnes
All of these appear to be taken from different sources.
Mural
As some have pointed out, there's a pastel-like quality that makes them look hand-drawn. This would indicate that if it was real, all three would be Mural-taken. What's interesting about this is detecting the corners of these pictures and attempting to correlate them with the Mural.
Mural -
Shadow appears to be in front of Roy or Marth's cape, as that's where the most harsh red/black is, and his background is red/black.
Ken appears to be near a bluish white, which is consistent with the coloring near Ganondorf and Jr..
Isaac appears to be near whitish red with some green pixel in the corner. This is the first part of the leak that irks me since very little of that color exists on the mural. There's traces of it near Shulk/Peach, and we have to keep in mind that renders move, but the shading of the color seems to be consistent whereas even the brief blue/red on Ken/Shadow shift in tone.
Blurred Images
What sticks out to me here is that Isabelle and Skull Kid are unexplainably blurry. This means that these were not taken as part of the same image, as they are clearly not mural characters.
I can't explain Chorus Men or Agnes because it looks like one detail of their greater images have been unexplainably cropped, but this isn't unusal since we have other groups that aren't taken from the same source. Does that make it fake? Well, here's my verdict:
1: This goes off into the night without anything else dropping.
2: Source images for these pics turn up since they were all obviously cropped. A source image with more detail would give us more information to determine the legitimacy of this leak.
The main issue with an ESRB leak comparison at the moment is the fact that there's not even detailed pictures. People are welcome to argue the current renders don't look great, but remember that this happens with every leak, legitimate or not, and saying "Ken looks weird" when Ken is notorious for inconsistent/wonky designs doesn't strengthen your case that this is real/fake.
I have no idea at the moment. Either more will drop or more won't, and if we go 48-72 hours without any more, this is probably a fake. We could also see somebody confess that this is fake like the Springman/Decidueye leak.
Basically, if this is real, somebody has a large amount of source images they will likely be sharing later.