"New" A40 TCM compatible with locked ECU tunes

Hey guys, Quick question here. Have an LMM with locked tunes from Danville. Begged for the code just to be able to adjust some things for driveability in the TCM. Mainly part throttle upshifts and lock/unlock points. Understandably they refuse to let the code out so I am stuck with what I have.

My main question is if I reflash or "write my own" tcu tune, will it be able to work correctly with locked ecu tunes?,

The ECM and TCM are locked/secured independently. The locking only prevents reading/flashing - it has no effect on the operation of the ECM/TCM.
if one or the other is locked it won't affect the interoperability of either.
So if your ECM is locked and your TCM is not then you can edit/flash the TCM and will will continue to work with the ECM.

Reards
Paul

Awesome, thank you paul!