I'm no lawyer, but that sounds like the sort of thing that would've come out very early during discovery, whether she posted about it on Twitter or not. If it was in any way a formal investigation, Vic might've already known who was "running" it. But even if he did not know it, I just don't see it remaining a secret for very long after subpoenas actually start getting served.
I'm also not sure how much it changes, really. This isn't going to be a wrongful termination suit; they didn't need a reason to fire Vic. They could've held the most ridiculous farce of an investigation ever and just told him to hit the road and seek employment elsewhere. Where they screwed up, though, was by publicly stating (implying it in a way that a reasonable person would understand, anyway) that they were firing him because of his misconduct. Then that isn't just him losing one job; it's a serious affront to his reputation, and affects his ability to gain future work. That potentially becomes defamatory.
I think it's pretty clear that none of them have been consulting with (or at least following the advice of) any sort of competent legal counsel at any step of this process.