For those needs - My choice would be a good wool shirt over a T shirt of wool or bamboo ... possibly even cotton ... with a Ventile jacket or smock.
I do not think you could beat layered Wool, linen, bamboo under a Ventile outer - it is what I go for year around.
OK my mountain days are over now but in the lowlands this mix is unbeatable for comfort, performance and eco cred.
Looking at my coat rack it is all Ventile .. and I live in the heart of Wet Wales, only a short hour or so from what is now recognised from genuine Temperate Rain-forest (not joking here - look it up!): my EDC overtrousers are double Ventile.
If I am not wearing a Ventile top then
a - it is in my bag and it is the Welsh annual half day of summer
b - I am indoors
c - I am in my hammock
Other than the jacket I made myself my favourite currently available Ventile top is the Snugpack Westwinds Antarctic Smock (a review should be popping up here soon
)
My other favourite is the no longer available Bison Bushcraft jacket.
For wool I would look at the Bison shirts (I do not have one myself but make my own or commission custom models from my local Welsh Wool Mill) Wool and Bamboo T-shirts from Aldi
If you want to go cotton (or Poly cotton) for shirts and trousers I prefer 5.11 as the cut fits me perfectly
Wool, bamboo,or Modal shreddies are out there too (Sue-me do some great stuff) and the comfort is better than you may think.
Unless you want to go silly lightweight then there are natural alternatives for everything - even tarps and groundsheets