I read this last night, but had a hard time knowing what to say.
I felt much the same way about what was happening with my DS7's 1st grade teacher. It was a very bad situation. And we pulled him out of her class for homeschooling mid-year. I'm not sure that's a helpful story for you to hear though...
If you're going to advocate, then I think you need to try to get on the same team as the teacher. It sounds like that's not going to be an easy thing to do because you're angry and she's defensive and possibly acting punitively toward your DS11. That can be a hard situation to come back from.
I think I would apologize to her for the Native American thing. It sounds like she thinks you just ignored her, and that probably puts you in a very bad light with her. That's not where you want to be with her right now.
I do think that if you were asking if it was okay and if you explained your family situation and research into your Native American heritage, then you and your DS were not wrong to try to use that. (Provided you asked first.) But right and wrong don't matter right now. What matters is building a bridge with this teacher.
Keep your eye on the goal: improving your child's educational situation. Everything else is secondary! Let go of your anger and focus on improving the situation.
Easier said than done, I know...
