All you need is a +12 volt feed to the any 12 volt light. Instead of grounding the ground lead, you connect it to the tan (normally) on the overheat switch. If an overheat occurs, the temp switch closes, which grounds the light and the buzzer setting them off. There is no interaction between the two. Here is a simple diagram to do this. NOTE: This will not work if you have a temperature GAUGE. Temperature gauges require a tenperature "sender" (a resistive element) instead of a temperature sensitive switch.
Excellent. I was (as usual) over-thinking it. Any idea how much current can pass through the temperature switch? If I use LEDs, I doubt I would reach it, but is something to (over) think about.