Anchorman, if all the lamps associated with the key-on test are ok, that leaves the two untested ones and the i-light circuit to consider.
The Temp indicator lamp is part of the temp gauge, and is triggered by a switch in the same engine temp sensor that signals the gauge. It is located 2nd from the front, under the intake manifold, the only one having two wire connections. The wide connector goes to the gauge, and the narrow one to the lamp. If the Temp lamp is blown (and how would you know), either of the following could cause your i-light problem:
1) the temp sensor is failed (the lamp could have been blown for a long time, and the sensor just shorted);
2) the wire leading to the lamp (and, incidentally, to an input on the ECU labeled "115degC") could have shorted to ground somewhere.
Here's something to try. With engine cold, key off, remove the narrow of the two wire connectors on the sensor and measure the resistance from the sensor terminal to ground (it should be infinite resistance). Then with engine off, key on, ground the wire leading to the lamp (the Temp lamp should go on, and the i-light should remain off).
That's the easy test. If the i-light stays on, it could mean #2 above, or either of the following.
There could be a similar coincident-fault problem with the Air bag lamp and trigger, but I'm not sure how to test them. It looks like you could test the lamp via Pin 1 on the Diag. plug (but I'm not sure). Or, there could be a problem on the instrumentation circuit board.