Skip the school and camps - I threatened to send my son to boarding school once if he didn't shape up and he asked me "When do I leave". He was about 9 at that time. Ultimately he knew I would not do it (aside from the fact that I couldn't afford it).
So I turned to the tried and true method of taking away privileges. Not just for a day, or a week, but until his behavior changed and stayed changed. Took him a month, with lots or starts and stops, to display a consistently improved attitude. The beauty of this, for me, was it put the burden of behavior changes on him - if he changed he got his privileges back. No fussing, yelling, or continued threats from me.
I also realized that my son does not do well with multiple part commands. E.g., Clean your room, do the laundry, feed the dogs. Too many things strung together and nothing gets done. So I made it a point to tell him I have a few things that you need to do. The first one is .... When the first was completed I told him the 2nd one, and so forth. This worked better for us until he got into the habit of what he needed to do. Then I could just remind him to do his chores.
Oh, occasionally he does blow his chores off, but for the most part he is pretty reliable about them. The biggest problem we have had lately is my picking up some of his chores since I have been laid off. He got out of the habit of some of his regular chores and now I have to constantly remind him to do them. My bad, literally, so I am working on being more consistent again.
Try the chore charts, visual reminders often work well with children. Sit her down and talk to her about the shared responsibilities of being a member of the household. I really like the mantra suggestion - turns out I have been doing that without realizing it. LOL
Once again try counseling - we have done that on and off. I call it a emotional checkup - just like he gets a physical checkup. It has helped both of us to talk to an objective third party.
As for schoolwork - I am still fighting that battle with mine at 14 years old. He understands that if he fails, he will have to repeat - I will not allow him to catch up or make up in summer school. Again, set clear consequences that you can stick to. Make sure she has a place to do her homework every night - I use the kitchen table as going off to their rooms leaves to much room for goofing off. If she has a planner talk to the teachers about checking it every day to ensure she has written her assignments down so you know what homework she has. Then check and be sure she has completed it each night. We struggled with this - there were some nights it was 10pm and he was still sitting at the kitchen table doing homework because he goofed off so much. It only took a couple of late nights for him to realize that it was easier just to complete the work then have Mommy make him stay up.
I think they all go through a defiant stage - yours sounds more strong willed than most. But with consistency things should get better.