Situation has been resolved. I was able to pull a U0100 code with the V2, with the CAN location reporting the fuel system control module. I followed all of the CAN wiring and checked ever connector along the route. Turned out there were two little pebbles inside on of the connectors that I'd removed during the mechanical work that weren't allowing the connector to fully seat, though the cam lock was engaged. Fired right up, all of my error messages disappeared, and I was able to finally connect to the ECM. Lesson learned!

Thanks for the prompt help from you folks!