I am impressed you held your words with the boatlift douche. I would have "outed" the STBX right there. It is none of his business.
You are handling this so well. Newcomers need to follow your lead.
There is no way he has NOT talked to a lawyer, he is smarter than that. He is not filing because he knows the consequences of doing so. The idea of responding to his filing at his "secret" apt is pretty cool.