Do you want the ears to serve as a pillow cover? Will you want to take the pillows out in order to be able to easily wash them? If so, maybe you could crochet the entire blanket, ears and all, as one large piece. Then, you could crochet the back of the pillow cover and crochet the two separate pieces of the pillow cover together, leaving an opening where the actual pillow would slide in that could be buttoned closed. If you did that, you could easily adjust the shape of the back of the pillow cover to suit whichever shape you need the ears to be.
Does that make sense, or did I just muddle up your whole question?