By the diagnosis steps you've described I would feel fairly confident that you've isolated the problem to the speakers in question.
If I were in your shoes, I'd disconnect the power, remove the cabinets from the venue, and depending on whether you still have warranty or what your electronics skill level is, remove the amplifier plate and start troubleshooting (or send away for repair if still under warranty or you aren't 100% confident in what you're doing).
Are you sure the shock is static, and not an electrically charged chassis from some kind of power supply failure? If it were that type of failure I'd expect the whole thing to be DOA, but thought I'd ask. I have no direct experience troubleshooting this brand/model of speaker.
Static discharge can take out DSP chipsets in the right circumstances, and it sounds to me like the issue is after the input (you mentioned visible confirmation of signal reaching the input), so it could be the output section of the amplifier or the DSP section....or something else entirely.