I think the WTBS has shot itself in the foot.
I did some research on clergy-penitent privilige. The definition of "clergy" is up in the air, Watchtower elders may not qualify. If the Court takes this case this will likely be one of the arguments.
The bigger problem is that the Watchtower has told elders to report child abuse in states where they are required to do so. This can be taken as evidence that they don't have any deep seated doctrinal problem about doing so. All, or almost all, states now have some version of mandatory reporting. I don't think the WTBS can now claim that doesn't apply to them, they've already admitted it does.