Hi Chernoble, I also have 2 cats, 8 years old. I feed them a home-made raw chicken recipe a few times a week; the rest of their diet is quality can food: Wellness, Merrick Before grain, Evo, Eagle Pack, etc. There is stool in my 2 litter boxes every other day. I rarely see some every day so in my opinion, your cats are reacting normally to their new diet.
Also, don't be surprised if Shadow and Ranger drink less water. When Kira and Jadzia ate kibble, they would drink often. I changed to the new diet several years ago and since that time, I have never seen them drink from the water bowl... They are getting the water they need directly from the food, which is better for them.
