Thank you for all of this info.

Where do you find 12% H2O2, and what quantity do you recommend? Local stores only seem to carry the standard 3%. Might have to go with Amazon:
https://www.amazon.com/12-Hydrogen-Peroxide-Solution-Ecofriendly/dp/B09HZD2P96/

I'm going to knock out the glass block windows on the back of the house where the problem began, and install a new one with a vent. The vent opening is only 13" x 5".
Would this be enough space for the lay flat duct?

Or I could wait to replace the window and use the entire 34" x 8" opening to push all of the air/drywall through while remediating. That might not be a big enough opening for roughly 200 square feet of drywall, but that's also a lot of bags I could possibly avoid.