"Automatic transmissions are smarter than all drivers, and most mechanics"! That's a quote from my father, who was the first man in Nashville Tennessee to work on automatics, back in the late 1940's. That's still true today. Any linkage that gets it into Drive, Reverse, and Park will get the job done- - - - -anything fancier is just something to play with. Rig up a plain old cable operated shifter from something like a Pinto, and cut the pockets out of your pants. The trans will shift just fine, and your plaything will be more fun than a stick shift!
Jerry