I first stared this last year. Didn't get to finish, though. But now it's finally done! I greatly enjoyed making Screw Loose the most. The look on her face is just so silly! Oh, and that not-so-hidden Derpy too.
It's official. Not just fandom. But that still doesn't address the fact that he mentioned all the characters depicted within the portrait. By simple matter of a process of elimination, you might deduce who's who. This is hardly Sherlockian level investigations.