Hi, Helen. Welcome to the site. When you can, do a sig for yourself so it can appear at the foot of your posts, so we can always understand your own family situation (the one that brought you here). It saves explaining it all to us over again.
I'm glad you have the ADHD under control, but it does sound like there is more going on, possibly even more than the ODD.
Here is the suggestion that gets made to just about every new member - get hold of "The Explosive Child" by Ross Greene. It's not a cure, by any means, but it IS a different way of looking at these kids and handling them more effectively. For an advance preview, you will find some discussion about this book on the Early Childhood forum. The techniques in that book can also be used on PCs, so it shouldn't be making any more work for you. In fact, it should make things a bit easier for you.
A lot of girls go through the "I hate boys" stage, it's almost a fashion. I would be looking to her peer group to see where this is coming from. It shouldn't involve members of the family, though. We went through a similar stage with easy child when she was 9 or 10, because she was ganging up with friends to bully her little sister, easy child 2/difficult child 2. We finally took her aside and said that while you might fight with your sister at home, while outside the home you should always support your siblings and stick up for them. Family loyalty is most important - how would you feel if your parents publicly bullied you, in front of their adult friends? Or publicly put you down, called you a crybaby to the local grocer or shoe salesman, told everyone how they hated you because you're ugly and a pain in the neck. Brothers have feelings too, and they do come in very handy when they're older. Besides, with "I hate boys" - a good answer should be, "Brothers don't count," or "That shouldn't apply to brothers."
You can always use the line from "The Nanny" - "Don't be mean to your sister. One day your father is going to be old and sick - you're going to want him to live with her."
I do wonder if there is a lot of peer pressure happening in other areas - not easy if her social skills are poor, she is in a vulnerable position and could easily be taken advantage of by unscrupulous 'friends'.
Does she have a therapist of any sort? She sounds like she's just not coping, and needs some outside help in getting a better understanding of herself. It also can help with social skills.
With discipline, if something isn't working, don't use it. Also, don't try to control too much at a time - choose a handful of issues only, work with those and let the rest wait for a while. Try to use encouragement and praise where you can, rather than criticising her afterwards. Working with her on things can help, giving her choices can help. For example, I give difficult child 3 a choice - "We have two jobs that need to be done now. The birds need to be fed and the vegetables need to be peeled. I will do one if you do the other. Which job will you do? When the jobs are both done, we can play a game."
If he responds by refusing to do either job, then I will have to do both which will take me twice as long, so we won't have time for a game. Natural consequences, rather than punishment, because he can easily see why he's missing out on the game.
As a result, difficult child 3 is happier to do chores under these conditions, because he doesn't feel like he's being singled out and made to work like a slave. It also makes him more willing to help out at other times because he has learnt that I do a lot to help him and I am openly thankful when he chooses to help me.
Sometimes he's hungry and I am busy. I might say, "difficult child 3, I will get you some nachos when I've finished this job, but I won't finish for at least another half hour. Why don't you get nachos for yourself? You can come and ask me what to do next if you need it, I'm just a bit tied down at the moment."
Again, I gave him choice. He is a bit nervous about using the oven griller which is why he prefers me to do it, but depending on how hungry he is, he will sometimes go ahead and do it himself (often grumbling - I ignore that). When he does it, I often say, "That was a good thing you did. You did it well, too, I am proud of you learning to cook for yourself like that. And that way, you got to eat much sooner than if you had waited for me."
We've had far fewer rages this way. it's till far from perfect, but he can see how it works now. Most of the time when he rages, he is reacting out of fear or frustration. Again, I tend to ignore any apparent rudeness if I feel it's coming from fear or frustration, but once he is calm I will gently correct him.
Another example - such a small thing. He was opening his mail and it was schoolwork corrected and returned by his teacher (he's a correspondence student). They ALWAYS seem to use stickytape to hold the pages together, which really annoys him. He said to me, "Get the scissors for me."
I got the scissors but gently reminded him, "You should say, 'PLEASE get the scissors,' you need to remember your manners."
He immediately mumbled, "Please get the scissors," and "Thanks" as I handed them over. He wasn't meaning to be rude, it's just that his need was very immediate and he just didn't think. If I had reacted with any anger, it would have escalated him to tantrum level and he would have learned nothing - in fact, he would have felt righteously indignant and we all would have been upset for nothing.
What we do - he's still learning appropriate behaviour because I model it for him. He learns "Do as I do". But by helping him keep calm, I'm also getting more effective learning from him as well.
Back in mainstream he was often getting upset at school - either by other kids in the playground, or a teacher who might be more authoritarian than most, ruling by fear or iron control. That sort of control does not work well for difficult children, they hate feeling subjugated for its own sake. I still burn inside when I remember teachers from my childhood who frankly, bullied their students to get what they wanted. I remember with fondness those who taught with love and compassion. I also remember the subject matter from them much better.
Multiply that by ten or more, and that could be how your daughter is feeling at school and maybe life in general. It's not easy - in fact, sometimes it seems insurmountable.
Your daughter should be entitled to some level of support in the classroom, depending on her needs. I can only speak for the Aussie system but in this, it's similar to the US model.
Anyway, welcome, you will find support and help here.
Marg