The only way a lawyer can help you change your company's review process is if that process very specifically discriminates against protected classes, such as race, disability, religion, gender and so on. If the process doesn't discriminate this way, then it doesn't matter how unfair or bad it is, there's nothing you and every single lawyer in the US all together can do about it - while it may be a bad process, while it may be an unfair process, it is most definitely NOT an illegal process.
I've been reading your posts here pretty carefully, and while it seems there might be a bit of retaliatory action happening on the part of your supervisor, I think your company is doing whatever it can to ensure that you're not adversely affected (meaning that you're no worse off than your coworkers) by this alleged retaliatory action. I think you just oughtta go back to work, and stop obsessing about this supervisor. If you continue to try and find a way to sue your company (for this reason, for that reason, for whatever new reason you happen to think of next), you're gonna end up being fired. And this will be legal.