could be diabetes, kidney failure, urinary tract infection

When my cat Y.Lee started missing the box (he also would sometimes make it to the box) it turned out to be diabetes. It makes them have to pee more and he could not always make it to the box. Are there any other symptoms that you can relay to your vet. Such as: is he eating? is he eating MORE than normal? is he drinking? Is he drinking MORE than usual? Is he throwing up? Does he have diarrhea? How is his activity level? Does he appear in pain?