They are like solar panels that provide the real food (light-energy) for the plant. There is little that you can other than adding more lights or a mover. The reflected light the lower leaves are getting is better than nothing. If they get too little light, they will just die when not needed any more. So, my advice is to do nothing.
NO IT WOULD NOT! One of the first things I was told about growing marijuana is that under no circumstances do you line your room/box with tin foil. Apparently, the light can reflect off and concentrate in one area, burning your leafs. I would go with Mylar if you can afford it (if not, you can go to a grocery store and buy a bunch of mylar balloons. it might be cheaper and to my knowledge it works) or just paint the surrounding area with flat white paint.
tuck and fold...i always try and tuck fan leaves under budsites or stems...healthy fan leaves = big healthy buds!!! Try to avoid cutting healthy leaves from your plants. just MHO