Chicken has become one of my favorite things to smoke. I hardly ever smoked chicken before I had the SI. Those are all good questions, and I think you have to try some things and find what you like. It varies from person to person. Here are my experiences/opinions. All you really need in your brine for it to do it's job is salt. I also am a strong believer in brown sugar. That being said, most of the time I add other things to the brine to infuse flavor. They need to be strongly flavored things to really have much effect, like garlic, onion, certain herbs and spices, etc. Skip things like carrot, etc in the brine. They won't do anything. Any flavor agents you add to your brine will be relatively subtle in the meat, so go ahead and season the outside as usual, minus the salt. I do find that the smoke flavor is concentrated in the skin, and the skin does impede a little bit of smoke penetration from the outside, but I've never felt the chicken wasn't smoky enough (except for maybe the breast meat closest to the bone). You might want to try 2 chickens, one with skin, and one without to see what you prefer. If you are removing the skin, I'd remove it before brining. I have always left the skin on assuming it helps protect the meat and keep it moist, but I don't eat the skin. Unless you like eating leather and paper, you should give the skin to the dog. A mire poix perfumes the bird and adds moisture. Some people prefer to leave the cavity empty for more even smoke penetration, inside and out. Lately I've been adding a mire poix, but I've done it both ways, and I can see the point about the smoke getting inside the cavity. Either way is good for it's own reason.
