What are the parts highlighted in green, blue, and orange that are left of the engine in the image below? I was looking in the 2007 Nissan Maxima service manuals and could not identify them.
https://imgur.com/a/zmNavxD

Also, is it ok for the screw for the gauge highlighted in orange to be missing and the surround areas (highlighted in blue) covered with green liquid (coolant?)

 

and a new Schrader valve and or a new ac suction line