If Cowboy is actively using the character, I agree Cowboy should get priority. Not sure if Yuuki was aware of this when she proposed it. However, maybe this should be revisited in the sense of maybe Cowboy will want to adopt her, or if she doesn't Yuuki might later on down the road. Either way, whoever handles it, please do so in a gentle and respectful way that honors our friend and his creative design. Nashoba is missed, its good though that we can all speak openly when it comes to trying to preserve his legacy.