I have only just reintroduced dried food to my boys after my 8 year old was having trouble with UTI's and was found borderline for crystals 7 years ago.
The vet told me this was caused by the dry as it has a high protein content. He told me to, either stop all together or to buy prescription food. I chose to stop.
It was always given along with wet food and water, Now i only give it once in a while for a bit of variety
My mums female also has problems with going for a wee sometimes so she stops giving dry for a while and it seems to work avoiding any further discomfort.
Re The matting, Dont feel bad!
My Ragdoll (RIP) had really long hair, and he wouldn't let me brush him for love nor money. Used to end up really matted, down both sides, back of his legs and on his chest i had to book him in to the vets every March to get the mats removed under a general anesthetic, he didn't have much left by the time they were finished!!
My 8 year old cat is semi long haired and doesn't mind the brush but still gets slight matting on his hind legs.
I have a short haired cat who is 11 and doesn't groom so well now, He loves to be brushed and yet still has matting on his flank.
My 2 year old is also semi long haired and we haven't had any problems so far, but his coat hasn't fully grown yet so am expecting problems later on.
It happens and really you are not to blame. It cant always be avoided!
The trick is to get the undercoat out as this is what causes the matts and the best brush for this i have found is the furminator, expensive but worth every penny. It gets right into the undercoat to remove any dead hair.
It leaves hair silky smoothe afterwards