I can almost guarantee your microwave will not work on this circuit. It will snap the breaker like a dry twig. A micro hood combo will draw at least 1350 watts, and surely calls for a dedicated circuit. Just the micro and the existing lights will probably do it in alone. So you might consider putting micro on counter top, and plugging in the kitchen circuit your fridge is not on. Then you are right on track with switching changes for lights. You could run 14-2 and stub in center under each upper, right up against bottom of cabinet, these could run in a daisy chain, or you could run one for each cabinet back to j-box under counter. Then you could pick from several lights like flourescent or halogen. I'm sure we could find a little room in your panel for that new micro circuit, if you showed us a picture of it. Hey, good luck!