hmmmmmmmm....... seems to me that that aux thing under the 12v plug would be a button, not a stereo line in. Most likely to control auxillary lights. Its far from the stereo and aux switches and buttons are more commonly placed down there.
As far as my $.02 on ipod connection....go hardwired not FM transmitted. Only advantage of FM is that you can use it to get sub par sound quality on any FM radio. i.e. in your buddies 78 pinto with stock am/fm and silver buttons that look like buck teeth portruding 3/4 of an inch from the dash.
As this vehicle isnt on the market yet, you will likely have a hard time figuring out which is the right connector for your needs. I would wait, and see what kind of aux-in type connections are available on the stereo in your FJ. IMO best way to go is with an ipod specific adapter so you can control the ipod functions through the dash stereo buttons, your ipod will have a home in the compartment of your choice. No wires over the dash no flying ipod as you swerve to miss that dude drifting into your lane as he is on his cell phone, taking notes, eating a burger and smoking a ciggy all at the same time.