You my friend may be right, put your finger over it seen if the interior lights go dimmer.The roof covers are as said speakers for telephone, voice activation etc.
I'm not sure about the other item but can't see it being heating as it's now duel zone so would expect 2 sensors somewhere. I've not been out to look but could it be a sensor to dim/brighten dash lights in the day time, there used to be one in the rev counter on R56 models!
It should get dimmer because it doesn't need to be as bright in the dark. It needs to be brighter in sunlight to stand out.
Keep in mind that the Auto Climate adjusts for other things besides temperature, it also adjusts for humidity to avoid fogging and will react to a combination of inside and outside conditions. How it works specifically for dual zone I can't tell you but all auto climates need interior sensors.How does one sensor work for duel zone?