I’ve fixed the problems I outlined above. So, I’m going to call it finished, but critiques still very much appreciated. I feel there’s something off the lighting, but I’ve been looking at it too long now.
I think a lot of Pixar stuff uses Sub Surface Scattering and a heavy amount of Ambient Occlusion , they could both be lacking a little from your render. Also the purple looks like it needs to be pushed further in to the background. That said I like the colours you have chosen and well done for finishing a cool character.