>>2 In spite of what the hoaxers say, the Apollo spacecraft did have radiation shielding, it was some kind of fiberous substance like loft insulation material. The hoaxers seem to think that lead is the only viable radiation shield but you only really need lead shielding when dealing with intense gamma radiation. Alpha and Beta sources are blocked more easily (in fact a 6 cm thickness of air is enough for alpha usually).
Jack Swigart, Apollo 13 CMP died of leukemia so at least one Apollo astronaut did contract cancer. I don't know if this is just chance or if it's down to the radiation dose he took during his flight (Even with shielding the astronauts would have taken a radiation dose. Nobody pretended landing on the moon would be risk free).
3>> The flag would be just a pole and some nylon ash by now. The unfiltered UV light from the sun would have crumbled the flag to dusk years ago. Besides, there's no telescope that could resolve an object that small from so far away.