Drying out down bags in a floorless with stove

[DWP51]

a Well made Bivy should emit your vapors just fine. get one thats waterproof on the bottom with a light water repellent top that breathes really well.

Yessir.

When bivy sack is mentioned most people think of a mountaineering style one...

There are also ultralight bivy sacks that have waterproof bottoms and water resistant tops.
Borah Gear: Side Zipper Ultralight Bivy

This type of bivy is a great extra layer of protection and mine vents condensation extremely well and I put off moisture just thinking

I use mine in Western Washington inside a flourless shelter and it works very well. I also bring a Tyvek groundsheet for (sized for a sleeping pad) and it helps when I put it under the bivy as well, plus it has other uses too.