you can find out which wire does what by pinning them out.. listen to what everyone has told you here.
run a wideband sensor into EC18 like vems requires.. you are defeating the purpose of a built in wideband trying to use your aem.
keep the aem to watch while driving the car and tuning, you can see if you go lean and can get out of the throttle. however KEEP the vems wideband and use that in the datalogs to make adjustments to your map.
if it were my build i would keep the aem and vems widebands seperate with two sensors.. your harness doesnt sound to clean if your trying to run the aem and vems off of one sensor.. just a thought
