I'm scheduled for a court appearance to change my name in September. What do I bring besides the stuff they sent back to me? I assume ID but I've heard birth certificate? I have a foreign birth certificate and a naturalization certificate.

If you have those items in your possession I'd go ahead and bring them (but don't worry if you'd need to obtain a copy for example). The foreign birth certificate will probably be irrelevant (your naturalization certificate would be what you'd use to show that you're legally in the country and a citizen).