I am just curious on what these two sensors are directly behind the mirror and the one below the mirror?

 

The one on the reverse mirror in the first picture coincides with the sensor on the front of the reverse mirror and they are for the electrochromatic mirrors. The one on the back detects oncoming light, and the one on the front detects bright lights coming from people behind you. When it is bright in the back and dark in the front, your two side mirrors and your reverse mirror darken to protect your eyes.

the big camera thing in the second picture is for the automatic highbeams. You activate it by pushing the turn signal stalk forward and a green AUTO light should appear in the instrument cluster. Your headlights also need to be set to auto

 

The sensor on and directly behind the mirror is for the anti-glare operation of the mirror. I do not know what the other if for. It may have something to do with rain sensing wipers or automatic high bean sensing but I do not have either feature so I am not sure. You can always check your owner's manual for this kind of information.