Whatever the process, there is always lots of curiosity about the confidential tenure review process. In some institutions there is a great deal of openness, in others much less so. People want to know who is on the tenure review committee at the upper levels, who wrote letters of reference, what their chair or dean said in the letters. I am sure that Tenure, a People-like magazine, would do well, with pictures of provosts in incriminating situations, with stories about how people went on with their lives after denial, and with accounts of who was involved with who--gays and the like now replaced by fraternization, relationships between ranks, and how the dean's "boy-toy" is doing now that he is on his own. Still...
The most important person on your tenure committees is actually not on any of the committees. That person is you. If you do what you are supposed to do, or if you do not, you determine whether or not you receive tenure. If you are on the border, then you have given control and power to others.
It is not hard to discern what you need to do to be tenured:
Decent teaching and attentiveness to student concerns.
Showing up at faculty meetings, or other service obligations. If you are put in charge of something, do it acceptably well.
If you are given too large a set of teaching and service obligations, be sure the dean and chair appreciate that you understand that they are making your future much less sure.
Adequate grant performance. In some fields, none are expected. In some, internal university grants are fine. And in some, external grants from the right sources are expected. Often, more than one. Expectations are often honored in the breach, but you want to have a strong rather than a marginal case.
Reputation among important people in your field is positive and they know of you. You have to go to meetings, meet people, get invited to give talks, send out pre-prints or reprints.
Significant contribution to your field. In the arts, this may involve performances or exhibitions or published books--with reviews that are serious. In the conventional scholarly fields, a set of publications that make a contribution to the field, what is sometimes called an advance. It should be clear that you have major responsibility for joint endeavors. In the professional schools, there may be demands for practice, for publication in the main service journals in the profession, for the relevance of your work to actual practice.
Yes, this is lots to do in the 5 1/2 to 9 1/2 years of probationary time. But in that time, you might be able to generate job offers from elsewhere (peer or better institutions or departments are what is impressive). If you are at one of the institutions that makes tenure decisions after you are an associate professor, it is quite likely that you have such offers. (So you are up at Harvard, but have a Chicago offer. At MIT, Stanford or Berkeley are offering. Usually, at this stage, it is tenured professorship.)
And you want to be sure that you take time out for having children, taking care of seriously ill family members, or perhaps you are ill yourself. Many institutions stop the tenure clock with no prejudice for a year, at least.
If you are not tenured, you should be able to find a position elsewhere. Decide if you wish to continue as an academic. If not, go on to a terrific life. If you do continue, make sure your former colleagues regret their decision. As for legal and grievance matters, you need the counsel of those who know your institution, and your own taste for litigation. Would you write a book or publish several articles with that time and energy. Keep in mind that we overvalue what we have, especially if it might be taken away from us.
Living well is the best revenge. Actually, living well is all that matters.
PS I know there is meanness, unfairness, arbitrariness, and discrimination-- But you want to be in command of your career. Again, I have no idea how to respond to such behavior. A friend says to me if the his university allows such, he does not want to be part of it, and he is looking elsewhere. A provost's nightmare is when the strongest faculty are actively looking--they will have the most choices, and once a leak starts, a flood is likely. Losing 2 or 3% of your faculty, when they are your strongest faculty, is usually a sign that the provost should retire to become a president.