If I see some unknown person on my property and in my judgement attempting to commit a crime or committing a crime it is an immediate necessity, to me, to confront the criminal....
Immediate necessity is not a prerequisite for justifying confrontation per se--only the use of force, or the threat of force.
....to confront the criminal with a firearm as long as I have or had a "reasonable belief" that deadly force may be needed to protect myself or my property.
Forget "had"--that's not "immediate".
But what
you might consider reasonable is just part of it. What would
others decide that a reasonable person,
knowing what you knew at the time, have done?
If they walk away? I would still attempt to detain them
You would have no legal right to do so unless you are a sworn officer within your jurisdiction, and then you would need a lawful reason. Trespass does not constitute a lawful reason.
If I reasonably believed they actually committed a crime or attempted to commit a crime on my property the state statue on deadly force still applies.
No, it does not. The operative words are
prevent and
protect.
We are reminded of the Texas airline mechanic who,
with complete justification, left the safety of his home armed with a shotgun to investigate noises indicating an immediate threat to his tangible, movable property at night. He was shot and stabbed, and he lost an arm. The question was not one of his abilities with a firearm, or of his confidence in those abilities.
The risks involved in leaving the safety of your home are serious and manifold. You could easily be shot by one whose presence had been unknown to you. You could be shot by a first responder who had been summoned by someone else. You could use deadly force and fail in your defense of justification because it was determined by others that
your actions constituted the initiation of the confrontation--a confrontation that you could have avoided. You could be responsible for an unintentional discharge of a firearm. You could be charged with and convicted of illegally restraining the individuals. You could be shot by a trespasser, who may well be justified in doing so in self defense under the law.
All downside, no upside.
By the way, while the unfortunate Mr. Horn, mentioned in your ABC News link,
believed that he had been justified in trying to protect property of others, he may well not have been. The case was dropped because of the testimony of an LEO witness who stated that he saw Horn fire in self defense. And Horn ended up a ruined man.
The next Grand Jury may well have decided differently.