While most of what you have written relates to civil rather than criminal
issues, there is no doubt that blackmail/extortion is a criminal offense. There can sometimes be, however, a fine line between legitimate settlement negotiations and extortion. Still, you you have nothing to lose by reporting the matter to the FBI at the field office nearest to where this has been taking place. (See link)
If they think the matter is not something they want to prosecute, they will tell you that and suggest that you resolve this matter in civil court where the case is pending.
It also appears that the plaintiff attorney's conduct with regard to this case may be unethical. I'm thinking specifically of his having sat on the case as judge, transferring it and then becoming the plaintiff's attorney. You might want to report that to his bar for investigation
Neither of these, however, should be done without conferring with your lawyer on this case, as you can create unintended and unwelcome consequences when you stir up something like this. If your lawyer tells you not to do this, you should listen.