Following this thread. I'm in the southeast and considering First Lite myself. Generally doesn't get under 20 during the season, maybe not even under 30 much. Interested to see what folks recommend.
My 2 favorite First Lite outerwear pieces I got this year were the Source Jacket and the Solitude Vest. The combo of the two should cover most of your weather except rain.
As far as base layers their Kiln Hoody is very nice.