To the original question...
Murder: not guilty, other issue is irrelevant. Everyone has the right to defend themselves, and to use any tool to facilitate survival. He certainly had fair warning that such a situation may occur, but one is/should not be required to vacate one's home for any reason.
Felon in possession: separate case, not guilty. Law has a principle whereby a law may be disobeyed if obeying it would cause greater harm than not obeying. In this case, he was forbidden weapons, but circumstances proved he would likely be dead if he obeyed that law.
As a juror, I contend that the Constitution trumps; the "felon in possession" law is constitutionally invalid: no other point in the Bill Of Rights is similarly lost to felons, neither should RKBA. Voting rights may be lost, but they are a construct for our governmental system, as contrasted with natural rights independent of governmental system. Sentence served should restore citizenship; if someone's still too dangerous, leave 'em in the cage. Some are released on certain agreements, but those are backed up by a return to the cage if the agreement is violated.
It's absurd to let him off for shooting someone in justified defense, but to convict him for having the tool he needed for shooting someone in justified defense.
To the landlord/bouncer case...
It's all about reasonable doubt. The jury is directed to give a guilty verdict ONLY if beyond a reasonable doubt. We can't prove the threat to kill the wife, but we can conclude, from circumstantial evidence, there is a reasonable chance that the landlord acted appropriately (albeit unusually).
To jury nullification...
Our government is a system of checks and balances. It starts with voters - and ends with voters. Voters put legislators, executives, and judges in power, and trust them to govern in a manner representing the voters' wishes. If, after all the legal wrangling proceeds, someone ends up accused of violating the law, the jury (made of voters) have the opportunity to evaluate whether the law has indeed been broken ... and whether the law has so twisted the voters' intent that it should be invalidated in the given case. "If you don't like the law, vote to change it" may be too long and too unlikely to address a current case; all too often people are convicted of crimes not because they are guilty as voters intended the law to apply, but because an unintentional conflux of mismatching laws and unfaithful representatives can be twisted to net a prosecutor a conviction for his personal benefit. Remember, laws are typically written by people who really don't understand the subject at hand. Don't let the force of law unavoidably crush the innocent when the intent of law deviates from the implementation thereof.
As for following the instructions of the court: that extends further than what the presiding judge says. "Ignorance of the law is no excuse" - if I know the law, and I know it contradicts what the judge says, then I side with the law ... which happens to say I can say "not guilty" if I believe the law would be wrongfully applied in the given case. I cannot be both expected to obey the law wherever it applies, yet ignore the law when deciding (as a juror) whether it applies. Honoring my oath does not mean blind irrational immoral obedience to a superior whom I know is giving wrong directions.
And I can't believe I just read someone contend that, where CCW is illegal in churches, someone should be jailed for felony murder for having a gun which they used to stop a murderous rampage in a church. That is EXACTLY the kind of perverse outcome of law we need jury nullification for.
"I was just following orders" is reprehensible when those orders are plainly unjust.
More on felons & guns...
The "felons shouldn't have guns" line helps perpetuate the mythos that guns are unusually dangerous. Felons are not forbidden knives, clubs, etc. - but somehow guns are deemed a special case. This special treatment of guns spills over to us law-abiding folks, and helps justify the anti-gun crowd's push for prohibition. Allow the special case there, and you'll get it extended where you don't want it to be.
Upshot...
You can't sanely convict someone for having tools needed to protect his life, as demonstrated by their actual use. Any system that concludes otherwise DEFINITELY needs a safety valve (to wit: jury nullification).
"You can use it, but you can't have it" is just stupid. Especially when one's very survival is on the line.
), at which time they have as much right to SD as anyone else.