Welcome to the forum, to answer your questions:
First, I think you are describing one of the alarm switches, I do not remember exactly the color of the wires but, I wonder, why are they disconnected? you may be in for a surprise...
Second, the air cleaner housing comes as a unit only, you can check with auto recyclers like Potomac
http://www.pgauto.com for a used part.
Last, again I have to check but, I know the air conditioning hoses meet with the expansion valve in that area and it has three connections...
I let you know later if somebody has not giving you an answer yet...