I think at the first sign of kidneys problems in Yorkies, it isn't a bad idea to consider kidney diets. The ones you listed are probably the best choices.
You can try a "holistic" dog food (Natural Balance, Innova), but a veterinary nutritionist would need to look at it first to make sure that's a good choice. Otherwise they can formulate a homecooked recipe for you if you are really opposed to feeing rx diets.