Roger replied to my questions of Angora testing, "Now that you mention it, I have to say no. Interesting idea – just what should one test for I wonder? How well it resists being packed down or felted up would have to come into it I think."
Angora felts the least of many animal fibers because it has the smallest and least pronounced scales. I remember reading an Indian research paper wherein they were actually applying plasma treatment to Angora fibers, as to increase surface friction so that it could be spun easier and more efficiently, because apparently they viewed it as a cheap, easy to source, and fairly efficient alternative to down. I can look for the article. The problem with Angora is that it doesn't spin as well as other fibers–it's more slippery. It can be done, but it takes skill or specialized machinery. One could increase this slippery nature by application of a DWR–this is actually what i did with one of the quilts* i made.
Regarding compression etc, that is a good question for which i do not have an answer. It certainly will be better than Kapok, because it's less brittle/stiff, but doubt it's as good as even lower quality down because much of down is even finer than Angora fibers. However, the fact that it's got enough flexibility and strength to be spun and then knitted, seems to bode well for some durability in being compressed but also probably not as good as lower quality down.
It would shine more in smaller items like hats, mittens, jackets, etc, and not quilts or bags. I'm considering in the near future, combining Angora with polypropylene microfibers to see how that works. PP mostly because of extreme light weight, cheapness, decent durability, low moisture absorption, and because loose microfiber PP fibers are readily available in bulk quantities–because it's a common material added to concrete.
* I made a very odd quilt, out of a combo of 2.5 oz Apex, with Angora and 550 Duck down mixed together, while spraying the Angora with a fluorocarbon DWR (to decrease potential felting or matting issues). It ended up being heavier than i wanted it to be. I'm going to re-purpose the down and angora for smaller items.