If your dog is very sniffy, and sniffs absolutely everything, it could just be a reverse cough. Sniffing a lot can make the dog inhale something into its nose and down into its throat, causing it to cough and make strange noises. My dog had it for a while, but she's stopped. It's nothing major, from what I know. The loose stool could just be what you're feeding it. If you're feeding your dog a lot of something that's mushy, it will come out that way, and loosen it. I used to feed my dog peanutbutter as a treat all the time, but I ended up giving her too much too often, and it gave her a lot of loose stools. I don't know what you're feeding your dog, so I can't really say all that much.