Here's your negotiables. Two lbs is heavy for water bottles - guessing that's with water? - but you also have a bladder so I'd cut back to one bottle, just to mix electrolytes or as a backup for the bladder. Cookset depends on cooking style; you can go way lighter by getting a titanium or hard anodized liter (or less) pot and just boil water to have hot bevvies and rehydrate meals. Stove can be simplified by using alcohol stove; five or six grams for the stove, a few more for a windscreen, and the canisters go away.

What's in a three pound emergency kit?

Ditch the chair - go with a sit pad, inflatable or foam, or use the sleeping pad.

Three water purification methods? Lightest would be chemicals; my usual is a filter and some micropur tablets for backup in case of mechanical failure.

Take out one jacket. Use layering strategies; I have been comfortable in shoulder seasons with midweight unders for sleeping, nylon pants and short sleeve for hiking, a fleece of weight appropriate to expected temps, a windshirt, and a down or eVent jacket. Hiking with the shirt and windshirt has been warm for me and a poncho comes out if it rains.

Tent can be lightened quite a lot as can the sleeping pad. If you can't be comfortable on a foam (lightest but bulky) a NeoAir will knock two pounds off your total weight and pack down to a handful. Tent can be a tarptent if you must have a structured shelter (18 oz to 2.5 lbs, thereabouts) or a light solo tent or bivy. Some people just use a tarp that doubles as a poncho. I personally use a hammock and tarp.

Camera can be replaced with a small digital and make a huge weight savings, unless you absolutely must have the setup you use.

Sleeping bag depends on budget and lowest expected temps, but here, you will find that it's possible to be warm and light, inexpensive and warm enough, but never warm and light and inexpensive. Down will be expensive, high quality down very expensive, but will compress smaller, weigh less, and be warmer than synthetics, not to mention have a longer life span if taken care of. For a very good sleeping bag, Western Mountaineering or Montbell; for an entry level compromise between budget constraints and quality, Campmor has some down bags for less than two hundred. Big Agnes has some good options in down and synthetic, and save weight by only insulating the top half of the bag; you slide a pad into the pocket for bottom insulation. You can cut the bag weight in half without huge expense.

Once you make all the decisions on gear, you can figure out a lighter backpack to carry it. Granite Gear packs run about 3 lbs and carry up to 40 lbs (Nimbus series). Osprey and Gregory also have some lighter packs; they may work for you as well. The lightest packs will be ULA or Gossamer Gear semi-framed packs, where the sleeping pad becomes part of the frame. Those tend to be for loads of 30 lbs or less.