I have been with KIA now 2+ years. I am no mechanic, but across the parts counter, it seems the brake/stop lamp switch is a commone and easy fix on all KIAs.
Not saying that this is the fix to all of the above problems, but it will afect everything you guys have been saying.
The Fob battery wont stop the car from starting, when you put the FOB in the car. The chip that signals the car that it is ok to start is always functioning. When you put it in the craddle it will always start, dead FOB battery or not. The battery will stop the doors from locking and unlocking. That is a good idicator if it is the battery in the FOB or not.
Kia Parts eStore