Here are the materials in Griffith v. Caney Valley Public Schools (N.D. Okla.):
Oklahoma Religious Freedom Act
Federal Court Affirms Oklahoma School’s Refusal to Allow Native High School Graduate to Wear Eagle Feather on Graduation Cap
Here is the order in Griffith v. Caney Valley Public Schools (N.D. Okla.):
22. Order and Opinion (5-20-15)
Prior materials here.