I will try to keep this brief and I won't go into all of the details:
First, about whether to attend the JC meetings/appeal or not. (I have no doubt that you do not plan on attending given what you stated.) Some, including Lee Elder suggest not to attend, however, you should note that at least one court (canadian) has held that the plaintifff's not "exhausting all of their remedies" in the ecclesiatical process meant that the suit was not properly before the court of law. In other words, the guy lost in part because he did not attend the JC or appeal the decision that resulted in the DF'ng. (This is just a basic point of law, you almost always have to first exhaust all of your administrative procedure or in the case the ecceliastical procedure.) This doesn't mean that you have to physically attend though. IF YOU WANT TO HEDGE YOUR BETS, send the JC an official position statement in lieu of attending and likewise file a written appeal of the DF'ng and send or have your attorney attend the meetings on your behalf. All of that will be good enough. If they don't want to meet with your legal representative a court of law will not hold that against you. (of course we talking about retaining an attorney and spending some dough for his time. you may or may not want to do that.)
In the end though you are pretty much out of luck and are not going to win anything in a court of law or prevent any action of the Congregation/Society, even if you retain a lawyer.
In a Nutshell here are potential classic causes of action:
1. Defamation - generally a loser these days. I won't even get into all the reasons why this isn't a possiblity. (The only person who every succesfully sued the Society for defamation and won was Olin Moyle and that is because the Society was reallly really stupid in its conduct and actions.)
2. Alienation of Affection (Tort) - this is extremely extremely rare and mostly abridged by State laws that have removed it as a cause of action.
3. Breach of Contract - fuhgetabout it, it's a fairy tale
3. Intentional Infliction of Emotional Distress - Not a bad cause of action, this is probably what you mean by "harassment". The classic elements of IIED are that the Defendant's conduct was so "extreme and outrageous" (as considered by the average reasonable person) that it resulted in distress to a person of normal sensibilities. Sounds good but the first problem is that plaintiff must suffer severely and usually show bodily manifestations of the emotional distress.
4. Privacy torts (False Light, Intrusion into Seclusion, Public Disclosure of Private Fact, Commercial Appropriation): Most of these are economic related and have to do with controlling one's image/likeness for business reasons. But the Public Disclosure of Private Fact is promising. The main problem is that the announcement that "Seeker4 is no longer one of Jehovah's Witnesses" is not enough to qualify. False Light is another possiblity because it basically is the situation where it creates a "false" or inaccurate image or understanding of the Plaintiff. In this case, the DF'ng makes you unsociable but I think there is way too much is unstated and implied for any court to make the connection.
The bottom line here is this. No court is going to intervene with the inner workings of a church except under very extreme circumstances. In reality a DF'ing is a church action and an "internal matter" that only tangentially has any affect on you.
In other words the Congregation is not harrassing you (in a court of law's eyes) it is controlling/dealing with its own voluntary members. Informing them that you are no longer one of them is not something you can sue about even it it were not true. In this case, particularly you admit that it is very true, in fact you publicly admit you are not one of JW's.
So as far as the Congregation/Society's action of announcing what you have already admitted that is that. It would be like them announcing that the sky is blue today (on a clear blue day) as far as any legal point is concerned.
Of course we all know that the problem is not what their action is it is with the underlying policies and with the action of the members in compliance with those policies and that is the real rub with trying to challenge a disfellowshipping.
It is the VOLUNTARY ACTIONS OF THE MEMBERSHIP in compliance with their beliefs and JW policies that make them comply or be DF'd themselves that produces the effects of the Disfellowshipping action.
In other words, even if you could get to that point of the matter in any court, ultimately a court will tell you that the Society is not responsible for the actions of its members, even when the members HAVE to comply, because they could always CHOOSE NOT TO BELONG instead of compliance.
Ultimately the conclusion is that when it comes to Disfellowshipping/Shunning there is no legal basis and no winnable cause of action.
But having said that, it may not hurt to scare them if you can and if you can find an attorney who's ethics permit him or her to get involved, even though the likelihood for success is nihl. But I recommend that If you did want to do something, your best bet is to fight this not on the organizational level but on the personal level. Bring suit against the INDIVIDUALS involved and see if they will get the legal backing from the Society or not. If it turns out that the Society doesn't want to come to bat for them, they may let the matter go. But if you are going to do this you will have to scare them asap. Once it gets past the JC it will be over.
PS: I forgot to add the most important thing: You should really fight this on your own turf. Go to the newspaper with this juicy story if you aren't able to kabosh it legally. The resulting bad press will be a big black eye and at least it will be a pyrrhic victory for you.