Recommendation #2: pre-heat the cabin

Recommendation #3: if/when driving in stop&go traffic, use the regen energy directly for heating to save some charge/discharge cycles.

Recommendation #4: along with #2, use some phase change materials to “charge” some thermal batteries.

#1&2 are a thing. Not sure about 3 and 4.

3 may require some predictive modelling to know if you’ll be driving in stop&go or not.

I believe this is because most vehicles do a fixed amount of regen(which goes into the battery) when the foot is off the accelerator, but no additional electric braking when the brake pedal is used. I think that's because current regulations have pretty much stopped modifications to the braking system in cars, and prevent tweaking it to do electric braking when available to do cabin heating, and mechanical braking otherwise.

[1] - https://www.amazon.com/J-Jinpei-Lightweight-Intelligent-Temp...

I can't speak for all cars, but mine uses a heat pump for heat. Should have similar efficiency to A/C as that is exactly what a heat pump is.

http://cdn.agilitycms.com/mesca/productdownloads/mem-201806-... (page 13)

House geothermic heating is very similar, except the collector is buried under the ground where the temperature doesn't really go negative C (until -30C and depends on the soil, etc). Overall for EV cars in cold winters producing heat is a non-trivial task.