Hi there and thank you for your question. I am a licensed veterinarian and would be happy to assist you. Thank you for rescuing a dog with behavioral issues... many people would just euthanize them without trying. These questions are nearly impossible to give advice for without seeing the dog and doing a series of behavioral tests to see how the dog responds to each test, so it would be best to see a behaviorist in your area and have them come to your house and meet Holly. Here is a site that should help you locate one:
I hope this helps, and I wish you the best of luck with Holly! Take care.