Maybe this will give you an idea of what will work during your time on Camino. Below is a list of my "closet" that I carry in my pack. Besides it being used during my Caminos, it is about the same as what I used to thru hike the Pacific Crest Trail and the Colorado Trail (most of which sits above 9,000 feet / 2743 meters in elevation) into late fall. And for the thousands of other backpacking miles I have done.
- Pants -- REI, Classic Sahara Convertible, Zip-Off Legs
- Baselayer Top -- Smartwool, Lightweight, Long-Sleeve x 1
- Baselayer Bottom - Smartwool, Lightweight
- Hat - wool beanie
- Windshell Jacket - Patagonia, Houdini
- Insulating Layer -- Mountain Hardwear, Ghost Whisperer Vest
- Socks -- Smartwool Phd, Crew, Light Padding x 3
- Extra insoles x 1
- Poncho --- Frogg Toggs
- Gloves -- North Face, polartec
The total weight is around 3.4 pounds.
For the potential of February temperatures dipping into the 20's in the early mornings and at night at the higher elevations, I would add:
Mid-weight full zip fleece jacket
Wool Scarf
Insulated Hood
The additional weight would add about 17 more ounces. With my clothing, a 35F rated sleeping quilt, and the rest of my gear, it fits comfortably inside my Gossamer Gear Gorilla 40L backpack with plenty of room to spare.
The clothing that I wear usually consists of running shorts, and a long sleeved synthetic and lightweight shirt. If it is chilly out, my baselayer bottoms go underneath the shorts or I wear the pants, instead.
All of the clothing can be used in various layering configurations to provide a comfort range from 25F to very hot. This is just an example of how a layering system can be flexible and cover a wide temperature range which is more than sufficient for the time of year you are going, including up thru O Cebreiro and into Galicia.