This case will have less to do with the shunning that arose from the JC and more to do with whether or not Mr. Wall's civil rights were upheld in the elders' judicial process itself. The elders will be held responsible for the consequences of their action of disfellowshipping based on whether or not their process to arrive at that decision followed natural justice rules.
I can see the WT, if they haven't already done this, getting elders to sign some sort of release saying that any decisions made by a local JC be held solely libel and the WT is off the hook. In other words if anyone is ever sued would be the local JC, leaving the WT off the hook.