Unless gear lever is in park you can not remove the key, if you prise up the gear lever surround there is a black bar on the right of the lever you can lift up to mover lever into park position without having battery connected.
Really one for @jamesmartin but not been on for ages, think I remember seeing somewhere that the long stick 5 speed will fit but not without changing the tunnel, not much help to you maybe but best I got.
Had panel out on my 3.6 to drill hole for aux lead up to front foot well and as I said all those sockets are on a printed circuit so my thought would be maybe dry joint on aux socket to printed circuit, powerful have a video on how it comes apart.
I guess you have selected aux on the head unit so other thing to think about is circuit board that aux and 12v sockets are mounted on is damaged, time to pull it apart I think.
Sign still there, really nice chap retired couple of years ago now, when ever see door open now place is full of boxes but never seen any vans out side.
While part of me would like to agree I have to bear in mind the four post ramp, tyre changer and wheel balancing kit in his work shop all of which I have use of lol, got to say I have driven the J--P couple of times (paper bag on head of course ) before that gearbox went bang its a really smooth...