Yeah really long extention is about the only way to do (you’re going to curse like a mofo trying to get a socket back on that car). besides what has alraedy been said, if you have a helper with small hands have him up top and snake his arm behind the starter to where that bolt is (take the AFM out of course). while the person under the car is helen keller’ing the last bolt with the long ext (there is no visible path to it) the person up top can walk/guide it on the bolt. Same goes for the reinstall.
Also if you don’t give a darn about the rubber heat/noise dampening) mat between the body and the trans rip it out (if its real crusty like mine it’ll fall apart in your hands. while I couldn’t 100% confirm it there looked like there was a few straegically placed bumps in the sound deadener that got in the way of a clear the path to that bolt (intsall was a ton easier, could have just been the cussing taking it out though…)
Either way good luck and have a beer ready (you’ll need it)