Lynn,
I haven't been able to read through all of the posts because Ive only got a small period of "break" while while taking care of my kids so please forgive if it's already been said. I wanted to offer my 'gut reaction' to what may be going on here. I have read that there are certain normal N times in a person's life. One being infancy and the other, adolescence.
Now, I can certainly understand and empathize your fears that your daughter is becoming N like her dad but from what I have read, I certainly wouldn't jump to that conclusion. Like I said, this is a gut reaction so may be a tad un scientific. Your daughter is going through an enormously challenging time right now with the divorce of her dad plus when you add on adolescence, wham!!!

The fact that she acts in non N ways outside of the home further makes me think that she can definately be 'healed' of this period in her life.
My oldest daughter went through a similar phase when we moved cross country away from everyone she had come to know and love. Granted, she was only five, but there are still similarities. Her personality COMPLETELY changed and I stressed out to the point of full fledged panic that she was ADHD, a problem child, etc. Like your daughter, she challenged all of the rules and boundaries. And, like you, I knew that she was going through a tough time and gave her more leeway, not sure of how much to give and how much to not tolerate. She got really out of control. She developed selective mutism, refused to follow all of the rules, etc. I tried tightening up the reigns with her to the extreme and the behaviour didnt' stop. In fact, got worse. Finally, I just gave in to my heart and tried to
feel what she was feeling. Tried to see life through her eyes and realized that she was just a frightened girl trying to make sense of the disorder going on around her. So I gave her extra love. Had her sleep with me whenever she wanted, hugged her, held her for long stretches of time, kissed her. Lavished her with affection and love. But I also maintained the boundaries. The only difference being that the boundaries were gently told. Nothing was a punishment as her inner sorrow I felt was enough at that point. Boundaries were enforced but love was above all emphasized. Sure enough, she blossomed and grew out of that phase.
You may feel that there is little connection between a five year old and your daughter. But I see similarities. I think that, on top of being a normal teenager with all those hormones sloshing around, trying to make sense of a changing body and emotions, she also has to deal with the divorce of her father. I definately would not take this time as indicative of how she will end up being in the future.
She states that she cares first and foremost about herself and does not think about others. If others have a problem, they can fix it. She claims to have zero emotional reaction to others. The behavior that results is harsh, cool, abrasive.
This may be a defense reaction to what is going on in her life. Her way of protecting her fragile self right now. She may, simply be unable to deal with anything else at this point. Her plate is more than full. Take care,
-E