I'm no expert on the law, but just from a logical standpoint, it seems very reasonable to me that if an officer yells "STOP!" at a man who has just verbally threatened him with bodily injury ("I'm gonna kick your ass, you pig!") and is approaching the officer to do just that, the cop has a perfect right to shoot him dead. This is (at least morally) a no-brainer. As far as the law goes, well, the law and morals are seldom found in bed together anyway.
You just don't physically threaten a cop and not expect to take the dirt nap.
Back to my scenarios.........
In #1, I would still do the same exact thing. Y'all can run around dialing numbers while a maniac tears his way into your castle, your belongings, and your wife if you want to; I'm showing him that there are easier targets to be had. In that situation, 99 times out of 100, he will turn and flee, never to be heard of again. Those are damn nice odds, and they're the ones I'd be going with. In that split second, I don't have time and wits enough to think, "wait! what if he has a friend hiding with a rifle trained on my window?" or other crazy ideas like that. I'm addressing the IMMEDIATE situation. In a situation like this one, to think about things other than Mr. Nasty getting ready to level your door, kill you and your family and rob the castle, is just insane. Easy targets is what they are after. People with .45's and 00 buck shot aren't easy targets. I'm going with the odds here. This one is getting way too "what-if'd" by people. It's easy to sit at the keyboard and dream up possibilities of his friend sitting across the street with crosshairs on your chest, or the guy leaving but then coming back later, or that you are on Punk'd or Scare Tactics or something, but I still believe that most of us would not think like that when the time comes. In the moment of attack, all planning and thinking would be abandoned. It's not TFL forums anymore. Now it's innate. It's primal. We'd counter his threat with one of our own, and in all liklihood, that'd be the end of it.
#2 has too many variables to get people to commit to an answer as to what they think they'd do. I'll let that one go, but in #1.....I'm sticking to my guns.