2 hoodies with layers underneath will be more than enough. Of course it's Hood so you never know exactly how the weather will turn out, but I would say that on the windiest of days in July I've always been set with one or two T-shirts, a hoodie, and my shell. On a sunny day without wind, I would recommend starting with a t-shirt, hoodie, and shell, but know that you'll most likely be losing layers as the day goes on. A T-shirt and shell without a hoodie will be a good combo because you won't be too warm but you also won't stay soaked if you fall.
As for the sleeping stuff, it's up to you. I think when I was a camper I would bring either a sleeping bag or a couple thin blankets, that's it. The cabins are pretty warm and if you get cold you can just throw on a layer. I always just wadded up a hoodie or something for a pillow. Not the most comfortable but it worked.
You will have a lot of downtime at camp after skiing. My friends and I would skate all the time after coming back from the hill, so I recommend bringing your deck if skating is something you enjoy.