You probably need:
FADEC ECU, thermocouple, propane solenoid, fuel solenoid, and the RPM sensor board.
The stock TEMS ECU will have a thermnocouple that is ungrounded, and it MUST be ungrounded to work on a TEMS. (the shielding is not in contact with either of the leads within the thermocouple.) The thermocouple with a FADEC will be a K-type as well, but I'm not sure if it needs to be grounded or ungrounded (or if it even matters in that case). With the TEMS, if it had a grounded thermocouplle, it would cause a ground loop between the starter motor and the EGT, which made the ECU go haywire on startup.
Next, the TEMS ECU's RPM board may or may not be compatible. They are very similar circuits, but best to stick with the FADEC's hardware.
the Pump is probably transferable to the new ECU.
You are making a wise choice in swapping to a FADEC. Its a far superior ECU. (Like 10 years ago i use to service the older TEMS units...)
KW