The ex-pen or create is the right place for her when she is over-wound. And (and I know this is hard, especially with the kids) the sorrier you all feel for her, the more she is likely to keep it up. I wouldn't really call this separation anxiety. She's an over-exited baby who wants her way. The more you can TOTALLY ignore her when she's like this, the sooner she will stop.
She is WAY to young to be given any sort of freedom in the house if you want her to potty train quickly. The more accidents, the longer it will take. At this age, she needs to either be confined to a small space or tethered to you. It's all about creating good habits.
We'll keep putting her in the ex pen when she is crazy. I'll just help the kids understand that we need to ignore it.
As for the freedom, yes that was totally our fault. She won't be off leash again unless we are sitting with her and playing. I feel bad about putting her in the ex pen because she enjoys following me around and I enjoy having her around, but in the end it will be better.