New CX-5 user, got some questions please chip in

[Kedis82ZE8]

The system measures humidity - I think it may turn on initially to help dry the air, even when set to heat.

That very well could be the case as humidity was quite high that day. IIRC I had it on manual mode, dashboard vent, and AC was off (no LED indication)

 

[GAXIBM]

If you have roof rails and cross bars, they may add to wind noise so keep them to the back of roof. I think mud flaps add to noise. There are some threads here about adding sound insulation, especially on earlier models as they did a better insulation job on the 2016s (especially the GT or top line).