For every cursing there is a blessing through faith in His Providence.
Undeserved suffering is a common testing.
Consider Uriah. His record is now recorded in His Word as a testimony to all mankind of such an unjust predicament. He obviously will receive a crown in heaven for his perseverance.
It isn't lost on those surrounding the situation of David's sinfulness. When David invited Uriah to his home for dinner and encouraged him to spend the night with his wife, Uriah was dutiful and conscientious enough to assert he couldn't do such a thing as his brethren were still in the fight and he had to return to the front.
Later, when the battle was lost, and the Commanding General of the Israeli Army reported to David, the report addressed extremely obvious tactical blunders on the part of the Army's commanders.
(one such report was that valiant Israeli soldiers had been lost in battle when the old women poured boiling oil on the Israeli soldiers from atop the enemy walls. Obviously, the attack had failed to suppress the wall defenses before committing infantry into the assault. Such a blunder should have resulted in the immediate relief of those commanders for incompetence in battle command.
Instead, at the end of the report, the commander mentions that,, "Oh by the way, that Uriah fellow you sent down to us was killed in the same situation, (wink, wink...)".
A valuable lesson is to be found here. Even a believer who happens to fall out of fellowship by willful sinning, now becomes a target of other corrupt people who will attempt to further tempt and manipulate legitimate authority into corruption.
The Commander could read human character and immediately perceived something was afoot between David and Uriah, when he had been dispatched to the front. That commander just as picayunishly implied the murderous deed had been performed, in hope of a debt owed from his King for services rendered, even if they were criminal. Such is a worldly system of power, independent of God.
So David not only committed adultery with Bathsheeba, he also tried to conceal his sin by inviting Uriah back so any offspring would be confused as actually being Uriah's, but that plan failed due to Uriah's integrity. He then attempted to use Uriah's integrity as his weakness, by placing him in a position of likely failure. When observed by his fellow junior commanders, they perceived the corruption afoot, and attempted to aid and abet David's corruption by not only obeying his orders, but when they failed in battle, they sought to use Uriah's death as justification of their incompetence and failure.
Just as a man may commit adultery by how he looks at a woman, one may also be guilty of the sin of murder in our thinking. Not only was Did guilty of such a plot, he exercised action resulting in that death, so it also was premeditated and conspiratorial.
David was guilty of murder, adultery, and probably a litany of other sins associated with that incident.
The original issue is if we can lose salvation.
In order to properly understand the answer, one has to understand the vocabulary and doctrines of the terms used in the question.
You have a good grasp of many basic doctrines. I've found the question is more easily answered by studies of Common grace and Efficacious grace in their roles in our initial salvation and regeneration of our human spirit. Once created, that new man is eternal.
Nobody is ever condemned to the Lake of Fire for their personal sins. Those who fall out of fellowship don't "get away with something" by having already been saved. God has known every sin we would ever commit prior to salvation, when they were imputed upon Jesus Christ on the Cross and all Judged once and for all time.
The mere notion one can lose such a salvation stems from an unfaithful soulish anticipation of God's fiery indignation to sin and directing it at the sinner. THAT unfaithful thought arises because of original sin, where we now all have the knowledge of good and evil and are now tempted to substitute good and evil for our relationship with God in spirit by faith alone in Christ alone.
Those who doubt we can retain salvation are more prone to falling out of fellowship than criminal sinners, because they scar their souls into substituting their personal works for His work in us.
My answer to that is that we can guess a lot, and invite ourselves to err by reading something into Scripture that we cannot say is there. But refusing that temptation, we can say for a fact that we do not know Uriah's situation in detail enough to know whether or not he deserved the imminent call of the death angel. Nowhere in the story can we know what Uriah's standing before God was. Only God Himself knew that. But we can know what God's determined will for Him was, and that was his time, date, and mode of physical death.
However, we can also know that for whatever just and momentous eternal reason, Uriah's demise permitted the legitimate union of David and Bathsheba to produce four sons, the last of whom was the God-gifted Solomon from whose life flowed at least three wisdom guides to the followers of the Messiach, incorporated into our Bible, as well as the chronicles of Israel's history under his leadership.
It may be that had not David and Bathsheba been involved in this peccadillo, that God's plan already might have been for Uriah to die at the same time, place, and mode as he did; and that David and Bathsheba would wed without recrimination for it.
What I can read into the story is that between the lines I can guess that if Bathsheba had been more prudent in bathing and more faithful to Uriah by denying David's invitation, she probably could have avoided being embroiled in an adulterous situation.
And it was not particularly sensitive of Uriah to be seen offering a sharp reproach to his senior commanding officer for not being in the field with him, and furthermore of getting drunk rather than going home and having it out with his wife. Did he perhaps have an inkling of his home situation, and contrive this embarrassment to politically strike back at his king? Timewise, David seems not to have arranged a warrior's end for him until Uriah wrote his own death warrant, so to speak.
Who is it now that reads these characters' minds, or God's? It is not us, and we should avoid the temptation. With all respect, I do not see it necessary to have written a script as you have done here just to provide a provisional explanation.
Cvengr: The original issue is if we can lose salvation.
What we are to gain from this episode is that God's graciousness permits him to keep on saving those whose hearts and minds are fixed on Him and His trustworthiness, and thereby justified for all time and eternity, even through temporary and very serious lapses in dreading to disobey or disappoint Him, not fully anticipating the swiftness of His chastisement of His regenerated servants.
Cvengr: Those who doubt we can retain salvation are more prone to falling out of fellowship than criminal sinners, because they scar their souls into substituting their personal works for His work in us.
To me, it is clear that those who dismiss His power to do the saving must be treated as not yet having a justifying faith, nor the indwelling, comforting voice of the Holy Ghost.