Hi Ryan Great post. I've managed to figure out how to turn yucca fibers into soft fibers for yarn production. I learned this from an old online 1960s study on the Wetherill Mesa and fibers they found on the site. I talked about it in this thread months ago with pictures of the fibers.
This works best with younger leaves for softer fibers but can be done with older leaves but might require a bit more work. The fibers can get very soft. Sun drying bleaching the fibers also makes them turn out very beautifully white.
https://permies.com/t/58819/works-making-yarn-plants