So back to your question. The answer is yes, and the scan tool can activate the battery heater apparently for an indefinite period of time, but it seems one of the conditions of it initiating the battery heater relay is having the car plugged into an EVSE. I plugged it into my level 2 EVSE, the level 1 might work to. It would seem you can have it activate in run mode and then disconnect the EVSE and the heater appeared to sill function until I gave it the command to stop through the scan tool. I am not sure if you can concurrently activate the coolant pumps while battery heater is on, didn't try. Kinda cool but I am not sure this is an effective forced battery pre condition method, maybe under certain conditions.
As a side note it has some interesting BMS module tests of the traction battery, I suspect this is exactly what the dealer service technician has access to.
My battery passed all the tests, cool.