So very sorry this happened to you! After all the hours you've put into the quilt, it is heartbreaking when something like this happens. Hopefully the suggestion of the anti-static spray helps.
I've used the RJR Cotton Supreme numerous times along with RJR Jinny Beyer fabrics and never had a bearding problem. I usually use Warm and Plush, or sometimes Pellon Nature's Touch 100% Cotton, so very different from the wool that you've chosen. I'm not a prewasher of fabric or batting, and I usually use Aurifil 50wt or Connecting Threads' Essential Cotton.
Hopefully someone can help with a solution for you. The anti-static spray from the link Barb in Louisiana sounds cheap and promising!