Hand knit or machine knit medium thickness sweaters can have a fair bit of loft and spring to them, and breath well when uncovered and drain and squeeze dry nicely if soaked, and once you add a fleece or wind layer over they provide their full benefit for warmth. You get a little more puffiness or loft if the eventual wind layer has elastic cuffs and is just a bit short than the wool to fluff it up a bit. Maybe try same idea with a machine knit wool blanket vs a woven blanket. You could separate the wool and nylon shell for drying.

I would like to try using cat-tails as insulation some time.