@labradors,
Management can't tell you who to be friends with. Period.
In fact, management has very little say in what you do outside of working hours, so long as it's not illegal or damaging company equipment or reputation. Want to go to strip clubs? Picket Chik-fil-A? Cosplay as Jabba the Hutt? Management can't say boo - except for the question about company reputation. But that's an incredibly fuzzy thing. You have freedom of speech, press, and association. But management can understandably get upset if you use those freedoms to tell all and sundry that the competition makes a better product.
So, given the context of a potential lawsuit, this woman is wisely treading lightly. The rest of it is kinda gossipy. While it would be nice for her to tell everyone about how they done her wrong (if it even happened that way at all), she just plain can't.
You can be friends with her. I would highly recommend keeping non-lawsuit and non-job things out of your conversations, though. That's not for you to keep your job (management really can't police that, nor should they); it's more to make things more comfortable for this woman.
Or you can find other work.