Liz, I'm so glad that such a sweetheart dog has found her forever home with you...especially as you are so prepared to work caringly but firmly on her behaviours. And it's so true, she's had such a confused time in her short life. The suggestions from Carrie & the others are so good & helpful.
We've had 2 dogs which came from 'privileged' backgrounds...from top breeders who showed them. But they had problems like separation anxiety & dominance (too much). We followed along with knowledgeable advice about dog training & now some years later, their behaviour is great. So wonderful dogs emerge from all the work you put into caring behaviour training. And your sweetheart will be even more of a sweetheart! Please keep in touch to tell us how things are going.