With regard to the controversy about low protein kidney diets, you can compare the diets to the AAFCO standards . AAFCO specifies a minimum level of protein, and all the kidney diets that I found data for on the web (Hills, IAMS, Royal Canin) exceed this minimum. For example, on a dry mass basis, the AAFCO standard specifies minimum 26 % protein for adult maintenance, and the Royal Canin renal (wet, in pouches) has 34% protein (dry mass).

I suspect (but haven't checked) that they have less protein than typical feline maintenance diets.