If the following works passing thru your firewalls, well...I suppose
You could try to use the admin API
Myself, I did setup a remote Node-RED and I communicate successfully with that instance via a public MQTT cloud service (HiveMQ). From a local NodeRED instance I can check if the remote is online or not, ask for the complete flow as well as separate tabs, update existing or add newtabs and some other specific tasks like getting complete chart data. All communication goes thru the MQTT cloud service and I have not opened any ports in the firewalls
