Wow, just wow!
You managed to produce an absolutely stunning picture.
I love everything about it, I don't even know where to start.
First of all: the characters. It clearly shows that you created each and every character with an equal amount of passion and professionalism. Each character has its own personality and yet you fit them together so well (and of course, thank you for including my character).
The composition is just great, it doesn't look crowded even though there are so many things going on.
The background is also beautifully done. It has a nice amount of detail but doesn't take away the focus from the characters.
All in all, I think this picture is a great example of your talent and a perfect example of the Paper Mario style and your own.