There remains exactly one piece of evidence that Robbi cheated, and that is "no one would ever make that call without knowing the opponent's exact hand".
Everything else is theorizing, not evidence. It's telling stories about what's possible and then finding facts which fit the theory. But those same facts fit many theories, including theories in which there was no cheating. If a fact can support two opposing stories then it's not evidence for either of them.
Even the latest discovery - that one of the staffers who knew all the cards is dishonest - is not evidence that Robbi cheated. It makes certain theories (such as "She got tipped off by someone on staff") more possible (that theory couldn't be true if a staffer weren't dishonest) but it doesn't make those theories more likely.
By all means, theorize. Come up with stories. Look for facts that fit the stories. That's how investigations work, whether scientific or criminal. But never get confused between facts which fit your stories, and facts which necessarily imply your stories. The former are ideas which might lead to possible scenarios; the latter are evidence which can lead to conclusions. "Nice theory, now show that it must be true, not that it might be true."