So, point by point…
Lights? If you know how to use one, they don’t give away your position. If you don’t know how to use one, it could…so learn how to use one.
Empty chamber: If you think you’re more likely to shoot yourself than be caught short in a deadly encounter…maybe carrying a gun isn’t for you. There’s great options in pepper sprays now.
Tampons: if you don’t have anything better at hand, they’re better than nothing. But why not get proper equipment (and the training to use it!) beforehand?
Dry fire: see the whole other thread…but if done properly (snap caps are cheap!), you’ve got nothing to worry about.
Leg shots: if the leg is the best target you have, take the shot. But other parts are better at getting a rapid stop.
Bigger Calibers: Look—all things being equal, bigger bullets make bigger holes, and the ammunition industry has been working for decades in making little bullets perform as well as big bullets. So, to say there isn’t a difference in how the bullets act is just untrue. That being said, the effectiveness in real life shoots, particularly with multiple hits made, is damn near negligible.
“Dutch Loading”: it’s silly. I call it “the preference of the terminally indecisive”. Get a good JHP and it will punch through just as much barrier as a FMJ. Additionally, it adds complexity into the system where there doesn’t need to be.