Your list isn't bad, at that time of year things could get cold, I'd look for a box foot/mummy bag in a -20C model. Look for one with a fleece type liner. IF you are too warm, you can always open it up, but if you are too cold well you freeze. You should be able to find one under 5 lbs

It can also be warmer, which can bring out the bugs. Bring along a mosquito heat net and a Thermacell

http://www.thermacell.com/products/mosquito-repellents/mosquito-repeller-accessories

the best bug deterrent I've ever found.