Regarding the charcoal canister. I have seen a thread here where guys are using fox body mustang charcoal canisters and mounting them on the fire wall side of the passenger inner fender sort of like the '76-'77.
I mounted this one from a 87-93 Mustang just like my 77. My Aero tank has a vent/roll-over valve on the top. I bent up metal line on the outside of the frame just like my 77. The CC will not hook up to the motor as there are no provisions on 98 Explorer 5.0 to do it... It will just be able to vent out the mushroom caps.