I love that all of you wanted to do so much work in color and push yourselves with that. HOWEVER- your overall drawing suffered as a result of trying to do so much. I think you all need to take more time with the humble pencil and paper and just draw the s**t out of at least one of these. Especially as this was an exploratory assignment, the goal is to learn as much if not more from drawing the itty bitty details as well as getting the big flashy colors and shapes. Go look at some Wayne Barlow ans Allen Williams drawings, then go through your reference again and spend a few (or more) hours on just one drawing of the full animal. And then when you think you are done- spend another hour or two on it.
Above all- concept artists must be able to draw like angels, so let's see what you can do with the basics. ;)