I ended up with an ultralight bag from Exped. I found that Sierra Designs isn't very honest about their PFC usage, because they advertise a lot about their down being PFC-free but they still coat the outer, and probably zippers, etc. Most people don't realize how ubiquitous PFC's have become in the outdoor gear industry. And it's way beyond outdoor gear. Dental floss, meat-packing paper--you name it, plastics are everywhere now. It's a huge byproduct of the petroleum industry and this is how they monetize their waste. For decades, chemists have been looking for qualities in the fossil fuel industry's trash, because the volume is astronomical and makes them billions of dollars in revenue.
As for the outdoor industry, PFC's is still the elephant in the room even though they were busted by Greenpeace in 2016. People just forget.
Also, the last time I checked with Feathered Friends a year ago, they are NOT PFC free. I wanted to like them, too. Except for that. So much for Leave No Trace.