Applaws is definitely only complementary - not complete, so PAH are wrong to say that it could be fed as the main food, but if Max is having biscuits too, then it should be fine. It was all my Sam would eat for a while, and although I knew it wasnt complete, at least I knew he was eating something. I don't know about whether its suitable for cats with renal probs, I would say doubtful as it doesnt have the correct calc to phos ratios, so would think phos is quite high.
There are some other applaws combos - i.e. chicken and pumkin, chicken and cheese, and there are fishy versions.