IMO, you have a lot of reasonable options. Which ones are best depend on desired insulation, fabric feel, odor control, drying speed, and durability (wrt laundering and/or potential daytime use).
When really lightweight will do it,my fav is silk, but Terramar silkweight or OR Echo t shirt work fine, too.
For a little more insulation, my fav is merino blend, but any good quality midweight long underwear will do. I increasingly go toward hoodies when looking for real warmth. Warmer than a shirt and a hat for the same weight and only a little less versatile.
If small differences in weight are of significant concern, let me know and I can weigh some things.