While some may argue for a defenseless homeowner, so far that has not been the case and I would not be among them if they show up. Unlike you I would never go "good shoot" because there is no such thing. Appropriate under the circumstances? I would say so but having to shoot is never "good".
There is no questionnaire but the various laws may or may not have some form of "duty to retreat". "I'm scared so I'll shoot and I know I'll get away with it" laws? Nope. The use deadly force needs to pass a "reasonable and prudent" standard and if you need an explanation of that is I can provide one.
In my state I have a duty to retreat but that also means that I could reasonably do so safely, again as determined by a reasonableness standard in context. Let's say that I am confronted with a person or persons who display threatening behavior and I have reason to believe that there is potential for escalation. I cannot get in that person's face and provoke then shoot without consequence. I would have mishandled the situation and am responsible for my actions. Words are not grounds for killing.
But
If I can "retreat", which legally means disengage to avoid deadly force? Then I must do so. I just leave. If however that person pursues and attempts to physically attack then there MAY be grounds for lethal force. MAY is emphasized because if it's some 9 year old throwing a tantrum, killing is not warranted as that person can be subdued without deadly force. That applies to others as well and takes into consideration the physical condition of the one being attacked. A 330 lb linebacker facing an unarmed elderly woman would not pass a reasonable test in most situations. On the other hand if the situation was reversed no one would expect ( despite protestations to the contrary) that she not use whatever means are necessary to protect herself that she has on her person. Unfortunately, right-wing violence is real and substantial and despite exceptions on the other side is mostly from your lot. That means people who should be able to use weapons in self-defense will be penalized once you are out. That will be a consequence of the collective lack of responsibility exercised by those who you support as a matter of cause and effect.
As you point out, there is a difference between provoking a fight, shooting and then claiming self-defense, and the duty to retreat. But there is no "I'm scared so I'll shoot and I know I'll get away with it" laws. Your decision to shoot always has to be found reasonable by a judge and jury. You can't just claim fear and a shoot be automatically legal. But, I disagree with saddling a person with the duty to retreat by default.
While no shoot is "good," it should be very much legal to shoot someone who is a reasonable threat your life or property. Yes, I said property. Theft would drop dramatically if thieves knew they could be shot. And why should my personal property, which government cannot unfairly seize, be something I can't legally protect with reasonable deadly force?
As for this particular case, at what point do we judge these young people,
"most of whom have significant criminal histories," based on their actions that got one of them killed, and not by the old fallacy that all lives are sacred? First degree murder? Maybe not, but something damn close. At least 2nd degree "depraved heart" murder.
I have almost zero sympathy for people who choose to criminally victimize and would hurt or kill their fellow man. I also have an eminence amount of anger at the parents, system and society who raise these young criminals with zero respect for their fellow human being.