About 2 or 3 weeks ago I started on a model of Modern Sonic The Hedgehog. I modeled this from background images of the Sonic Generations model. I’m almost done modeling, however I’m not sure how I should model the mouth since it moves from the right to left side of his muzzle depending on camera angle in recent games and CGI.
Looks really good.
But I prefer the real Sonic, the one from Master System/Genesis 
I think you should model the mouth where it would normally go, in the middle. The shifting position is just for style, I think, so for something on a non-moving model the middle seems like the appropriate place.
Modelling Sonic The hedgehog In Autodesk Maya,
https://www.youtube.com/watch?v=qpurCSq0z64
https://www.youtube.com/watch?v=wsqS5dhq2F0
https://www.youtube.com/watch?v=u19ZT1KH2LY