Good post, Midimykeys, you hit it right on the head.
As for the Yaris' stereo head displaying song information from and controlling an iPod, the AUX jack won't let you do it. Mini-stereo jacks like that are really just for passing audio signal straight through to the stareo, kinda like playing your iPod using an old cassette tape adapter.
If you want to be able to control the iPod with the stereo, you would need to get an iPod interface kit from Toyota. Instead of using the mini-stereo cable through the headphone jack, it uses the weird iPod interface jack at the bottom of your iPod. Here in Canada, they're about $300 from the dealer. If you're more of a do-it-yourself-er, you can get a pretty decent stereo from Alpine or Pioneer, plus a dash kit and an iPod adapter from
ebay for about $200.