Hand dyed yarn tends to have a little more personality, but I've not found anything so far that really affects the no-fade charms. Sometimes if I'm contracting something out, I have spells laid during the spinning and carding or weaving. They're more... imbued, permanent, at that point. Just like a lot of my chests are spelled in part during work and in part after.
Threats don't work on him. He's immune. Proper pureblood owl, him. He might have been a dog in a past life.