I have full sets of primary, secondary, and tail feathers for our screech owls, great horned owl, kestrel, redtail hawk, and ferruginous hawk. I am allowed to keep those feathers for only two purposes: 1) Imping. That's the process of repairing a broken feather. 2) Education. And the education HAS to be conservation oriented an accurately reflect Federal Regulations.
If I were to use one of those feathers on an arrow, it would cross the line into "personal use" and my entire federal permit could be pulled without warning.
Honestly, I do not believe a Native American could technically use raptor feathers for fletching, the exception as I read it has the exception for religious and ceremonial purposes only.
Remember, all it takes is for you to have ONE encounter with law enforcement over a small issue like this and your record will permanently paint you as a law breaker. If someone else in your part of the country shoots a raptor, your name will come up on the list of lawbreakers to look at. Every game check by an officer will be colored with his suspicion that "you are up to it again". You can't buy a reputation at any cost, but they are pretty easy to sell for cheap. Turkey feathers are cheap.