The Jam 2 is fine for the desert. I went thru and made some comments.
A word of advise, you should never (EVER!) include a camp chair on a gear list on a lightweight web-site. You may never live it down.
Some of my suggestions involve buying new ear, but most of them just mean leaving stuff behind.
Are you SOLO camping, or will you have a partner?
And, how long of a trip?
TarpTent Squall - A tent in the desert when there are no bugs? Take a tarp!
Groundsheet Tyvek 7.5 - Nix the ground-sheet
Backpack Osprey Aether 60 (2003) 56.0 - Much lighter packs are available, get a JAM2
Pot/Mugs/Bowls GSI Dualist 19.0 - What? Way overkill. Use ONE mug!!!
Soap/sponge 2.0 - Nix the sponge
Camp chair BigAgnes Cyclone 6.5 - Oh good grief, do NOT get on a lightweight web site and let people know you take a CHAIR?!?
Headlamp (w/ batteries) Petzl Tikka Plus 2.8 - Get a lighter lamp, like the petzl e+lite.
Survival Kit Adventure Medical S.O.L 4.6 - cut this WAY down to what you really might need
Water bladder Camelbak Omega 6.3 - Use a pair of platypus 2 liter bottles
Fleece Jacket Mountain Hardware Chill Factor 22.0 - get a down coat, fleece is like the chair!
Rain Jacket ArcTeryx Beta LT 20.0 - Get a lighter jacket, the $19 DRI-DUCKS is perfect for the desert.
Pack Towel 0.2 - nix, just take a bandana
3 extra AAA batteries 1.0 - Nix 'em, just be careful not to use your headlamp on high, you'll be fine
Sun Block 3.0 - Too much, take less.
Compass & Map 4.0 - Hmmmm, this weight seems too high...