Thanks for taking her! Does sound like she was badly treated previously. I can see where you are wanting to build her confidence by getting her some training and fun rag chasing, but considering her mental state, I would step back and just let her be. I would not put any demands on her whatsoever, and that includes trying to get her to play. It might take months, but if she has the drive, it won't shrivel up.
I know it is hard because having a pack, you need to instill rules and expectations, but it seems the slightest expectation from you shuts her down, so you'll have to manage her environment so that she ends up doing what you want and she gets to build her confidence because she is making 'right' choices.
It will take a lot of planning to go through a regular day, but I think that giving her a few weeks or months "off" will have a big pay-off in the end.