Yes, shareholders could sue for non-payment of the second dividend, which was declared. Of course no liquidating dividend has been declared. And I doubt it ever will be.
I would think they would have a difficult time finding an attorney knowing there was nothing to collect. That second dividend is a valid debt owed to the shareholders. I suspect someone that knows what rhey are doing could file a pro se case if they felt it was worth their time, effort and filing fee.