EverLite

Cumulus panyam 600 https://cumulus.equipment/eu_de/daunenschlafsacke-panyam-600.html Or WM, I have a Megalite but thats -2C and normally above that budget https://www.westernmountaineering.com/about/sleeping-bags-specification-chart/

>I was absolutely freezing all night >Current setup: 20° EE quilt There’s your problem, read more below. Others have said that your pad is the weak point, but at above freezing, it should have been adequate. However, if you are loosing heat to the ground, adding clothing layers really doesn’t help, so despite your seemingly overkill setup, the pad may in fact be the weak link. Otherwise (from a fellow cold sleeper) down pants make a huge difference for boosting the warmth of your sleep system. I know EE quilts work for many people, but ignoring their racism, the design sucks and has several features that compound negatively unless conditions are close to ideal/you are lucky/you are extremely skilled: -extremely long (12+ft) baffles that promote down shift and cold spots. Even if a baffle is perfectly filled there will be some down movement, and the larger the baffle, the larger this cold spot will be. Also, the U-shaped baffles are a straight up cost cutting decision since there are less chambers to fill (the high price does not reflect this). -no differential cut. Differential cut (smaller inner fabric, larger outer fabric) helps maintain the 3D shape of baffles and stabilizes down. No diff cut plus super long baffles equals even worse performance (unless down is perfectly distributed and stays that way). -limit rated. Quilt will sleep colder / be heavier than expected. Granted many makers use limit rating, but the best regarded ones don’t. Limit rating plus no diff cut plus long baffles equals bad performance. FWIW, I have a 20°F EE quilt and a 20°F WM bag. The bag sleeps true to the rating while the quilt looks like a straight up piece of crap next to it. Based on the performance and specs, I estimate I would have to upgrade to a 0°F quilt plus hood to get the same performance as the WM bag, but the quilt will be *heavier*, only $30 cheaper and still have all the bad design choices mentioned above.

I used a Western Moubtaineering -20F bag for Denali and Aconcagua. I would add a 0F bag to my quiver if I had unlimited money. Groundpad(s) are super important as you can lose a majority of the heat to the ground. For legs, you need a puffy pair of pants when temps drop below -10F. They don’t have to be down, but needs puffiness I used 8000m boots for Denali and glad I had them since temps were -30F and the wind was howling. I would have frostbite with anything less insulated. For Aconcagua, I used non-technical insulated boots that were light and warm and cheap. They would be awful on steep icy slopes, but not an issue on that peak. I usually wear cotton socks. Wool socks never made too much of a difference in an insulate boot and gave less room for me to wiggle my toes. Toe wiggling is important to prevent frostbite.

You probably want to target about 45 pound weight max for your pack. Take a look at weight savings vs upgrades. There are some cheap upgrades like a smart water bottle instead of the Nalgene. Nitecore NU20 or 25 headlamps are awesome. Other upgrades are expensive. So much depends if this is just a one time adventure, or if you plan to do more mountains. If it is one time, look for what is on sale. If you are seriously getting back into it, Western Mountaineering sleeping bags are the best. Something like this is a reasonable sub-3lb choice: https://www.steepandcheap.com/rab-neutrino-pro-700-sleeping-bag Definitely upgrade the pack. That is my least favorite pack I have ever used.

If you are brand new, get something cheap and on sale. Fair chance that you either will give up backpacking after a few trips or realize that you want to invest more in high-end gear.  You eventually need a quiver if tents, sleeping bags, and packs as no single one is great for all conditions.  For summer, I mainly use: flycreek 2p tent, Western Mountaineering 20 or 40F sleeping bags, and a daypack with side straps that cost about $60 and weighs roughly half a pound. 

Western Mountaineering mummy bag. I do a lot in shoulder season and these are very warm for the weight

Western Mountaineering, Feathered Friends or Marmot for bags. Enlightened Equipment, Hammock Gear or Katabatic for backpacking quilts. Not cheap but quality and comfortable.

I've been a quilt user for years, but if I were looking for sleeping bags, I would go with either Western Mountaineering or Feathered Friends. You absolutely get what you pay for with either brand. Awesome quality.

There isn’t really an absolute best, but I like Katabatic for a quilt and western mountaineering or feathered friends for a bag. I prefer quilts down to around the low 20s, bags below that. Having a pocket in your quilt for a sleeping pad seems silly to me.