According to Jehovah's Witnesses, How does God safely choose what to foreknow?

Jehovah’s Witnesses accept that God is omniscient. To be omniscient means that God knows all things, past, present and future, all the time. Nothing escapes His knowledge, including our thoughts and motives. However when it comes to foreknowledge, Jehovah’s Witnesses say that God does not choose to exercise it in all circumstances.

The reason is based on the assumption that a loving God would never have predestined Adam and Eve to be disobedient, thereby introducing sin, and consequently death, into the world. Jehovah elected not to know what Adam and Eve would do and simply waited to see how things would work out.

When God created the first human pair they were perfect, and God could look upon the result of all his creative work and find it “very good.” (Gen. 1:26, 31; Deut. 32:4) Rather than distrustfully concerning himself with what the human pair’s future actions would be, the record says that he “proceeded to rest.” (Gen. 2:2) He could do so since, by virtue of his almightiness and his supreme wisdom, no future action, circumstance or contingency could possibly present an insurmountable obstacle or an irremediable problem to block the realization of his sovereign purpose.—2 Chron. 20:6; Isa. 14:27; Dan. 4:35. https://wol.jw.org/en/wol/d/r1/lp-e/1200001549#h=4

Rather than think that Jehovah God predestined Adam and Eve to fail by disobeying him, they reason that he exercised his selective or discretionary powers of foreknowledge. In the link below they say that “to offer something very desirable to another person on conditions known beforehand to be unreachable, is recognized as both hypocritical and cruel.”

THE alternative to predestinarianism, namely, the selective or discretionary exercise of God’s powers of foreknowledge, would have to harmonize with God’s own righteous standards and be consistent with what he reveals of himself in his Word. In contrast with the theory of predestinarianism, a number of Bible texts point to an examination made by God of a situation then current and a decision made on the basis of such examination...

Selective foreknowledge means that God could choose not to foreknow indiscriminately all the future acts of his creatures. This would mean that, rather than all history from creation onward being a mere rerun of what had already been foreseen and foreordained, God could with all sincerity set before the first human pair the prospect of everlasting life in an earth free of wickedness. His instructions to his first human son and daughter to act as his perfect and sinless agents in filling the earth with their offspring and making it a paradise, as well as exercising control over the animal creation, could thus be expressed as the grant of a truly loving privilege and as his genuine desire toward them—not merely the giving of a commission that, on their part, was foredoomed to failure. God’s arranging for a test by means of the “tree of the knowledge of good and bad” and his creation of the “tree of life” in the garden of Eden also would not be meaningless or cynical acts, made so by his foreknowing that the human pair would sin and never be able to eat of the “tree of life.”—Gen. 1:28; 2:7-9, 15-17; 3:22-24. https://wol.jw.org/en/wol/d/r1/lp-e/1970567

The article posits that God did not foreknow Adam's disobedience, making the sacrifice of Jesus into a reaction, something that had to be set in motion after the event, whereas the Scripture declares that the Lamb was slain from before the foundation of the world and we (believers) were chosen in Christ before the foundation of the world.

From their publication ‘Insight into the Scriptures’ Volume 1, they ask “Does God know in advance everything that people will do?” Part of the answer is quoted below:

The view that God’s exercise of his foreknowledge is infinite and that he does foreordain the course and destiny of all individuals is known as predestinarianism. Its advocates reason that God’s divinity and perfection require that he be omniscient (all-knowing), not only respecting the past and present but also regarding the future. According to this concept, for him not to foreknow all matters in their minutest detail would evidence imperfection.

If the Creator of mankind had indeed exercised his power to foreknow all that history has seen since man’s creation, then the full weight of all the wickedness thereafter resulting was deliberately set in motion by God when he spoke the words: “Let us make man.” (Ge 1:26)... It is therefore not a question of ability, what God can foresee, foreknow, and foreordain, for “with God all things are possible.” (Mt 19:26) The question is what God sees fit to foresee, foreknow, and foreordain, for “everything that he delighted to do he has done.”—Ps 115:3.

[Because “God is love”] he exercises a genuinely open, kindly attitude toward all persons, he being desirous of their gaining salvation, until they prove themselves unworthy, beyond hope. https://wol.jw.org/en/wol/d/r1/lp-e/1200001549

You mention Voluntary Nescience. I had to look up the meaning of Alethic, which pertains to the various modalities of truth, such as the possibility or impossibility of something being true. A short extract from the following article explains:

Voluntary Nescience is the idea that “the future is alethically settled but nevertheless epistemically open for God because he has voluntarily chosen not to know truths about future contingents.” Some people try to base a dynamic concept of God’s experience on the curious notion that God chooses to remain ignorant of certain future events. According to this view, He could know the future exhaustively if He wanted to. It is there to be known. But He deliberately blocks certain events from His mind. For God to be God He must know everything He could know. He must know everything knowable. Consequently, a divine knowledge that is less than perfect is a contradiction in terms... https://crosstheology.wordpress.com/richard-rice-against-voluntary-nescience/

Your question asks HOW does God safely choose what to foreknow? How does He foreknow which things He must foreknow and which things He can safely leave unforeseen without resorting to the equivalent of guessing? Another way of phrasing this is, If God chooses to foreknow certain things from the set of all of the possible things that there are to foreknow how can He identify the critical items and choose to foreknow them without knowing what all of the non-critical items actually are?

They say: “According to this concept [predestinarianism], for him not to foreknow all matters in their minutest detail would evidence imperfection.” Which begs the question, is Jehovah therefore guilty of selective ignorance? Their answer: “It is therefore not a question of ability what to foreknow” but it is a question of “what God sees fit to foresee, foreknow, and foreordain”.

That is the only possible explanation I can find in their literature as to HOW Jehovah exercises his ability to foreknow and foreordain. It seems to be based on the Jehovah’s Witnesses interpretation of predestination, and since they reject that concept, then it must follow that Jehovah cannot possibly be guilty of predestining Adam and Eve to fail and sin. Their reasoning therefore leads them to conclude that Jehovah decided not to know how things would turn out. Jehovah elected not to know whether Adam and Eve would sin but waited to see how things would turn out.