I'll second the idea of buying a pack last - unless you see something you're really interested in at a great price. With that, as also suggested, if you see it for sale on Gear Swap, don't hesitate too long. In the time that it can take to research the item it can sell; this I know from experience. Know what you want so when it comes up, you can grab it.
With Gear Swap, one has to be both patient and quick and know/accept that, quite often, Murphy's Law will strike. A "cheaper one" will go up for sale right after you buy something used or you'll get tired of waiting, buy new, and 'then' see that item for sale at Gear Swap.
The GL Ultra 20 quilt is a nice piece of gear, especially for the price. It should fit your needs if you can keep it dry. I have one and like it.
I can't say anything about your tent list. Just be sure to read, read, read reviews, look for Youtube videos, etc - anything you can do if you can't actually see/feel the tent before you buy. Condensation can be tricky to deal with sometimes, so how a tent/tarp handles condensation (double wall vs. single wall, amount of ventilation, etc), for example, may be something you want to look into as you shop around.