The reserved pins on the module are clearly the programming pins for the ICD.
The LoRa and LoRaWAN code can be ported from IBM-LMIC or Semtech and flashed onto the PIC with minimal changes only related to the HAL.
For large quantities if one wants to run own code inside the PIC, then it is a viable option.
You would of course loose certification but maybe you are not concerned about that.