First, an overnight trip in a place & time of year where you aren't likely to get dangerous weather (except maybe heat?) is a good time to experiment. If you are missing some item or don't have quite enough food or maybe too much food, you can still get back to the car and have learned something.
Second, the most important thing to do is to buy a digital scale. Weigh everything and make a spreadsheet (there are lots of online options here for format, etc). Reducing weight + bulk is usually an aggregate of lots of little decisions and knowledge is key here. For example, if you already have 2 long sleeve shirts, but you know now that one weighs 6 oz and the other weighs 9 oz, you can save 3 oz very easily. Doesn't seem like much, but if you do that 5 times, you've saved a pound.
Suggestions on what to keep from your list for 1-night summer trip:
7.5' quads in qt ziploc
Suunto M-3D compass
Sunscreen (*smallest container you can find, or repackage)
Basic FA kit (*this should be no more than 2-3 oz, tops)
Mini bic lighter, storm matches in waterproof case, wetfire emergency tinder (*took out the LMF, redundant especially for a overnight trip)
3.5" locking blade pocket knife (*w/o the weight listed, I'm not sure if this is worth replacing or not)
2 pairs Smartwool socks (*are these short socks or the taller heavier socks? If short, take 2 of these. If tall, try just the liners you listed. The key is not to encase your feet to keep moisture out but to have socks + shoes that lets your feet breathe)
Arcteryx nylon climbing pants
Exofficio bxr briefs
Patagonia Cap 2 L/S crew
Under Armor poly t-shirt
Mtn Hardwear Stretch Torrent rain jacket (*this seems like a lot of jacket for AZ in the summer. You can buy a DriDucks jacket for $15.00, especially for something that might stay in the bottom of the pack).
Patagonia down sweater
OR windstopper gripper gloves
Merrell Trail Runners
MSR Hubba Hubba 2P tent, fly, poles, 6 mini groundhog stakes (*you already know this is heavy, especially for one person. Try the fly only set-up unless mosquitos are bad).
FF Hummingbird 20
Thermarest Ridgerest (*try just this on an overnighter)
MSR Titan kettle
MSR Titan mug
MSR coffee maker (guilty luxury, I *love* camp coffee)
Snow Peak Litemax, 100g canister
MSR Whisperlite Int'l, 20 oz fuel bottle
S2S aircraft aluminum spork
***This is a lot of weight + stuff for an overnighter. Without wanting to get new gear, it's hard to say what to cut.)
*2 1L plastic water bottles (I like Smartwater for the tall shape)
3L MSR Hydromedary hydration bladder (*leave empty until get to camp. There is a big caveat here -- I don't know the AZ area or how much water you need to bring to survive. Bring enough!)
20 Katydyn purification tabs (indv wrapped)
Black Diamond Nitro 22 (*I'm not sure with the Hubba Hubba + cook gear that you can get everything in, but give it a try!)
Edit: Welcome to BPL!