2012 T42 tcm 4l60e to 4l80e

I have a customer with a 2011 L96 6l80e. He wants to run a 4l80e and maintain VVT.

My thoughts are to convert the harness to a E38 (already done), add a T42 TCM and flash it with a 4l80e calibration from a 2009 express van.

I have a matching 2012 ecm and TCM (4l60e) LC9 I believe. I see that 2009 was last year for 4l80e. So, can I flash the 2012 TCM with the 2009 4l80e calibration, keep the 2012 ecm stock with VVT enabled and maintain all the sensors, pedal and maf which were the same for the L96?

OR do I need to convert everything to 2009 and then buy all new sensors, throttle, etc?

What