Any weight reduction is going to come at some additional sacrifice, but you seem willing & able....
The formula for weight reduction most often leads to the heaviest items first:
Shelter - You already have an excellent idea for reducing your shelter weight. Please let everyone know how the fabric works for you.
Pack - Jacob's idea of using a stuff sack with straps is on track. I have used a Paddlers Stow Sack with straps made from silnylon, as an overnight pack. Perhaps you could use leftover pieces of your tarp material to make the straps, or just tie some BMW Spectra cord to each corner and around the top, at the weight you'll be carrying the cord won't bite your shoulders.
Sleeping Bag - The Arc Edge is your heaviest item. You do not list any clothing carried, clothing and sleeping gear are best considered as a system. What weather do you expect? Do you need a sleeping bag at all?
Summer here in the midwest is hot and humid. Most summer weekends here, I only bring an Adventure Medical Kits ThermoLite Single Bivvy for sleeping in my hammock, which is the coolest (temperature, at the very least) way to sleep. It makes a great pillow behind my head (it usually stays right there) and if I actually get a chill during the night it is amazingly warm. At 6.5 ounces the Thermolite will save you 4.5 ounces over the Arc Edge, almost 15% of your total. For many trips, the Thermolite is the best value.
Your list is among the lightest I have ever seen. Please keep the rest of us informed of any improvements and changes.