Hi, Rahvin.
I think you check this out: www.BlairMcGregorBooks.com, she's Sandan in Shorei Kai, an Okinawan style and she is also a writer. I read only one of her book, but she is very good. She also offers help writing violence, so maybe she can offer something useful, since your story is pretty violent.
I think it is worth a shot anyway, because she is pretty successful both as a teacher and a writer.
Best wishes, jorkam.