Sometimes settlement agreements are filed with the court, sometimes they're not. In this case, the agreement itself should spell out what "confidential" means and whether the agreement is supposed to be filed with the court or not. If not, I would think that even though it's been public since it was filed, that it could be removed from the court's file if filing it was itself a breach of its own terms. And maybe you don't want to removed - it says what it says, and if the ase was settled, then doesn't it undercut the defendant's alleged breach of confidentiality?
As for the defendant's alleged defamatory statements, whether the judge will allow discovery on that issue is up to them.
It doesn't sound like you've got compensable damages here, and it's not enough to have some liability, you also need damages. The agreement may provide that the party needing to enforce the settlement is entitled to their legal fees, so hire a lawyer for help, and bill the defendant. Apparently you plan on relying on Avvo rather than hiring your own lawyer, but legal fees are the easiest thing to prove of your alleged damages, since you'll have a hard time quantifying the damages from "disassociation," preventing you from finding a job (how would any potential employer know about any of this?), and your relative's threats of violence. As for losing business, that's compensable, if you can prove the actual loss as well as the causation, which won't be easy, but regardless your earlier question indicated you were unsuccessfully looking for work.
Avvo doesn't pay us for these responses, and I'm not your lawyer just because I answer this question or respond to any follow-up comments. If you want to hire me, please contact me. Otherwise, please don't expect a further response. We need an actual written agreement to form an attorney-client relationship. I'm only licensed in CA and you shouldn't rely on this answer, since each state has different laws, each situation is fact specific, and it's impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue.
The examples you provide of losing business and having people disassociate themselves from a person as a result of defamatory material disclosed in violation of a confidential settlement agreement do seem like compensable damages. It is often hard to value the loss of personal relationships so if the settlement agreement doesn't spell it out then you would use ordinary measures of damages and a jury determination. As for loss of business, that is typically evaluated by proof of business before and after, customers had and lost, etc. You should definitely speak with an attorney. You may have a claim for breach of the settlement agreement and/or also a claim for defamation.