I was thinking about bluetooth for communication between the two edisons using NodeJS and MQTT-SN
According to Stephanie this is quite possible, but I've not tried it myself. Edison to Edison Bluetooth | Musings from Stephanie
Given that the deadline is looming I'm dropping that and using Wifi instead. Here's my list of references that seemed relavent whilst I was researching this topic.
https://www.npmjs.com/package/bluetoothctl
https://blog.benjamin-cabe.com/2017/01/16/using-mqtt-sn-over-ble-with-the-bbc-microbit
https://www.npmjs.com/package/noble
https://github.com/eelcocramer/node-bluetooth-serial-port
https://software.intel.com/en-us/articles/intel-edison-board-getting-started-with-bluetooth
