UPDATE: Just got off the phone with an Escalation Supervisor. I explicitly cited my three Case IDs and stated that I am meticulously documenting this timeline for corporate records and legal counsel, and will take further action if this is not resolved in a timely manner.
The supervisor stated there is no one higher to escalate to on the phones, but promised to communicate my exact statement directly to the App Review team to request an expedited review. If you are stuck, call in, reference your case numbers, and let them know you are documenting everything for counsel.
Will update if the status changes.