You posted the door striker which is a larger dimension than the hatch striker.
Go to auto zone are any other major auto parts store and ask for the Dorman
striker bolt bushing kit part # 38424 and it will have the hatch striker in it.
It's a good possibility that it's your rear main but before I'd replaced the rear main I'd double check to make sure it wasn't either your valve cover gasket or PCV that was leaking.
The vacuum has nothing to do with your temperature control knob.
The temperature control knob has a black shielded cable with wire inside that is either pushed or pulled when you turn temperature control knob.
Other than a rock getting picked up in the tread of the tire and getting thrown at the underside of the fender and leaving a big raised up area on the fender, I don't think there are any other major reasons.
The fenders will fit the problem is the front part of the fender where the fender extension goes is 3/4" shorter in lenght on the 91-93 than it is on the 87-90.
You'll also need different splash shields for the 91-93.
MAP vacuum line goes from sensor to the bottom of upper intake to the large vacuum port next to the hex shaped vacuum manifold.
The fuel pressure line is correct.
The vacuum for the EGR can be hoked up like that since you don't have any smog.
The line for the charcoal canister goes...