We have not seen the engine starting with the app yet. Even though the app says it "may" start if it is below -15ºC. It is normal to only have fan blowing cold air if below -15ºC.

 

I only tried this once so far this winter. I did notice that the steering wheel warmed up. Not sure if that was because of the blower or if the heater in the steering wheel kicked in. It was nice

 

Yes. The steering wheel does heat. But I have not seen the seats preheating.
I also have not figured out how to turn off the preheating after starting it from the app. There is no "stop" feature. Turning the car on and off, even driving a little didn't stop it. Never noticed that before probably because I normally end up driving long enough for the timer to stop on its own.