You can fill his Kong with pumpkin and his kibble and freeze it as his meal if you’d like, but if you want something more treat-like, then here is a link with some ideas:http://www.kongstuffing.com
As for his sensitive stomach, I would say the key is to introduce new ingredients very slowly. Only give him a tiny bit of something the fist time, and if that goes well then slowly increase the amount. If it gives him loose stool, discontinue that ingredient.
As for the beef and rice, it sounds like a good idea, but it should definitely be cooked if it is going into a Kong, and make sure it doesn’t make up too much of his diet. Good luck! 😀
