Sure wouldn't want to piss off the green box he looks big and angry
On that same pic I see that the rendered " floor" is blueish whilest de background( which is probably comped in is yellowish I would match the colors a bit more.
( keep in mind that the sun gives a hard direct yellowish light and depending on what the weather is, the atmosphere tends to give a blueish indirect light or a greyish one ( if the weather is crappy like here in the Netherlands) with soft shadows.
I don't know if the images are actual shots from your movie, but if it is, try to keep te characters on the same side of the screen on image 2 the yellow cardbox character is on the left while on the 3rd image it is on the right.
Looks promising though