If there are only two wires, there is only one "combination of wires". What is the point here? You either have a bad switch, burned out light bulb, or forgot to turn the breaker back on.

The "normal" install would be that you have live/neutral/ground coming into the box and live/neutral/ground coming out of the box. The neutral in will be connected to the neutral out. The live in will go to the switch and the live out will go from the other pole of the switch. The ground in will go to the ground on thee switch (and sometimes to the box) and to the ground out. If the original live/neutral/ground is actually going to the fixture and not the switch, then you would have a switch loop. You would only have 1 set of wires coming into the switch box. The live would go into the switch. The white wire would be marker black and be connected to the out of the switch. It needs to be marker black to show it is being used as a loop of the live and not as a neutral. The ground would go to the switch and sometime the box itself. It is important to note that if you use a switch loop, the wiring at the fixture will be live even when the switch is off. Either way works fine. Which one you use depends on where the power is actually coming from. If the rest of the circuit is in the wall, it is usually easier to use the first method. If the rest of the circuit is in the ceiling, it is usually easier to use the second method.

Yes, there are some timers that have a battery to run the timer and a hard switch rather than a semiconductor in them. Intermatic makes them but it costs few bucks more.

Unless I'm missing something, you're just pull the motion sensor and replace it with a regular switch. Connected the two wires (red, black) that now go to the motion sensor to the new switch. Doesn't matter which wire goes to which screw on the new switch. Make sure the new switch is grounded as well.