another way to get the texture of his body is to ice the cake normally, and use a crumpled paper towel to get the fur effect, just blot it on the frosting and pull it off, this would also take much less time than using a star tip for the whole cake, and you wouldn't have to be incredibly neat with the icing part. for his eyes, I might suggest just plain m & m's, you could either just use the dark brown ones that come in the pain m & m bag or if you have a candy store near you that sells different colored m&ms, you could get black ones there for the eyes. for the mouth/teeth, fondant would likely look best, but if you're not experienced in using it, it is frustrating and definitely not worth it, and sicne its such a small area, either a: buying premade fondant or b: making your own, would both be kind of a waste for about 6 inches total of fondant. you could likely just pipe on the design using a #2 writing tip and fill it in with it too, for the bouth, I would suggest drawing the square with the red icing, and then filling it in with a knife so it is smoother, and it would definitely take far less time than piping it. the teeth would be easy and quick with a round writing tip. All in all, it should be a fairly easy cake to make, and if you have any questions about anything I've said- feel free to pm me or email me or text.. my info is in the advisor section.
HTH!