I wouldn't worry too much about adding things to his diet...I think that alot of dog food emphasize how NOT to feed your dog or cat anything but kibble because it won't be "balanced" is another gimick for people to simply feed nothing but kibble....meaning...you'll keep buying more and more...
its how they make their money...I dunno..this might sound familiar..but I swear it...in my home country..dogs lived on people food..they got variety..everything from boiled potatoes to cooked chicken with raw vegetables and raw eggs...and they lived happily into their late teens... 16...17....18...
I'm not a fan of kibble..although I do feed it because of convenience...when I do have time, I prefer to cook for my dogs..all the things you have mentioned in your post I have and continue to feed to my dogs at one point or another...
Its not difficult to formulate your own meals for the pets..as long as you know what their daily nutritional requirements are...
sometimes, this helps alot:
http://www.nutritiondata.com