Sounds like you already pretty much have what you need. Keep those gift cards and cash for something you really want instead.
Any pair of nylon hiking pants will work fine. Zipoffs are nice if you prefer to hike in shorts during the day and then add the pant legs as the evening cools down.
A hiking shirt - polyester or nylon - you probably already have something that fits the bill. If have absolutely nothing synthetic then even a cotton tshirt is fine as long as you have another layer in your pack that you can switch into in case the t-shirt gets wet.
Spend the $20 on the DriDucks. Great lightweight rain jacket. Leave the pants at home.
You seem to be good on socks. 3 1/2 ounces for heavy sleeping socks is more warmth then you need, but just take 'em off if it gets too hot.
You have short and long undies - great.
For a sleep shirt anything will do: long underwear top, cotton T, fleece, whatever.
Gloves, you don't need them down to freezing. But if you have biking gloves those are good to protect your hands from sunburn during the day (especially important if you use poles and have the tops of your hands exposed to the sun all day) and add a bit of warmth around camp at night.
Insulation. Here is where you could spend real money. If you choose to. For now you probably already have a fleece in your closet. It will work just fine. Long underwear top, fleece and your new DriDucks jacket will keep you warm enough down to freezing.
When you do buy an insulation puffy piece (down or synthetic) it will be lighter and more compressible than your fleece. You are looking for something below 12 ounces in weight, there are lots of different ones to choose from. Wait until after xmas and you can probably pick one up for half price.
Hats, sounds like you have a beanie lying around, definitely bring it.
You also need a good sunhat. I wear something really dorky looking with a wide brim, makes me look like I belong out there. YMMV
Have fun, take lots of pictures, and report back here!