I don't see why you need to remove the A-pipe from the cat connection on the rear. You just need to remove the front ones (three bolts) holding the A-pipe to the exhaust manifold then unhook the rubber hanger near the flex pipe off the center beam, pull it down afterwards. This should give you sufficient amount of clearance to take the oil pan out. What you didn't do to make things easy for you is to remove the torque converter cover and the control cable holder cover off the tranny. No harm removing them and without these the pan should come off and go in smooth and easy. Put the covers back on when the pan is already in place. Done it many times, once to my car and several times on friends cars. The whole job takes less than 20 minutes.