Since you're thinking of apping an OC, I'm not sure how much an AU game would affect you, but bravenewworld is extremely OC friendly! We're a Pokemon game with a focus on world exploration, and encourage player plots. Right now, we're slow-to-medium paced (still new), but shapeshifters would actually be able to work quite well in-setting, as we have our own brand of shapeshifting crafted into the world.