1) How do we stop/get her to see that her method of relating to her friends is unacceptable? How can we teach her otherwise without nagging/punishment?
I'm in the throes of this challenge myself. It's tough, tough work -- and the rewards of good role modeling can take a while to show up. Direct lectures don't work (they didn't with me either ) so a lot of it has to get worked out in more skilled ways. Like talking about scenarios in movies, or helping GD with issues you see, or issues she will talk about. Or, if she tries to be controlling with you, bring up how it makes you feel, offer her an alternative way to speak to you. That kind of thing.
With my son, he picked up a lot of self-loathing from having a BPD dad who used shame as a parenting technique. I've had to be more creative and find ways that avoid shaming him. The validating questions section of the book You Don't Have To Make Everything All Better have helped. It was a big

moment when I realized that if I validate him, he will learn to do this in intimate relationships. "How do you think Friend felt when you played your game and he had nothing to do?"
I also put S14 in a skills group with other boys. At a certain point, kids will take what their peers say far more seriously. S14 had greasy hair for a while and I could not get that kid to shampoo his hair properly. I tried everything. Then one of the guys in the skills group made a comment, not a mean one, just a comment about how his hair looked greasy and/or wet. Problem solved.

2) are there any good books for adolescents that will teach her how to cope with bet mother's rages, no talking, scapegoating etc. Her mother is not a mild BPD and I think it's getting worse.
We have a book list that includes the following:
Book Review: Sometimes My Mommy Gets Angry
https://bpdfamily.com/message_board/index.php?topic=186318.0Book Review: The Weather House: Living with a Parent with Borderline Personality Disorder
https://bpdfamily.com/message_board/index.php?topic=223218.0Book Review: In My Corner of the Moon
https://bpdfamily.com/message_board/index.php?topic=209751.0Book Review: When Parents Have Problems: A Book for Teens and Older Children With an Abusive, Alcoholic, or Mentally Ill Parent
https://bpdfamily.com/message_board/index.php?topic=149775.0The hard thing about raising kids who may be at risk for BPD traits is that many of the parenting techniques we have in our skill set can't or don't work because they've been used with disastrous results by the BPD parent. I keep coming back to validation because it's the one skill that allows me to use all the other skills -- it evens out the jagged edges of consequences and helps me help S14 regulate his feelings enough so that he is receptive to my parenting. For that, this book is pretty good, although it does tend to linger a bit more on phrases/scenarios with younger kids.
Book Review: The Power of Validation (for parents)
The Power of Validation is detailed resource for parents seeking practical skills for validating their child’s feelings without condoning tantrums, selfishness, or out-of-control behavior. You’ll practice communicating with your child in ways that instantly impact his or her mood and help your child develop the essential self-validating skills that set the groundwork for confidence and self-esteem in adolescence and beyond. For all of us, learning to validate is a useful skill. If we are parents, whether parenting a child with BPD traits, parenting with a BPD partner or ex-partner, or parenting after having been raised by a parent with a PD, validation skills are especially important. Read more.
https://bpdfamily.com/message_board/index.php?topic=166930.0Members have also recommended this book too:
Book Review: Brain-based Parenting
The biggest challenge to parents, Hughes and Baylin explain, is learning how to regulate emotions that arise—feeling them deeply and honestly while staying grounded and aware enough to preserve the parent–child relationship. Stress, which can lead to “blocked” or dysfunctional care, can impede our brain’s inherent caregiving processes and negatively impact our ability to do this. While the parent–child relationship can generate deep empathy and the intense motivation to care for our children, it can also trigger self-defensive feelings rooted in our early attachment relationships, and give rise to “unparental” impulses.
https://bpdfamily.com/message_board/index.php?topic=195469.0