You are quoting errant thoughts with true and immutable scripture as though they are equals. Only one of your four quotes is scripture. The question is not "when does a child's heart become wicked?" it is "when does a wicked man's heart become like a child's?"

It is not the understanding of religion that saves a person, such understanding often dooms a person. God is not into religion, he is into relationship.

It seems like you have a quarrel with the Living God who says,

Eze 33:11-20 "Say unto them, As I live, saith the Lord GOD, I have no pleasure in the death of the wicked; but that the wicked turn from his way and live: turn ye, turn ye from your evil ways; for why will ye die, O house of Israel? Therefore, thou son of man, say unto the children of thy people, The righteousness of the righteous shall not deliver him in the day of his transgression: as for the wickedness of the wicked, he shall not fall thereby in the day that he turneth from his wickedness; neither shall the righteous be able to live for his righteousness in the day that he sinneth.

"When I shall say to the righteous, that he shall surely live; if he trust to his own righteousness, and commit iniquity, all his righteousnesses shall not be remembered; but for his iniquity that he hath committed, he shall die for it.

"Again, when I say unto the wicked, Thou shalt surely die; if he turn from his sin, and do that which is lawful and right; If the wicked restore the pledge, give again that he had robbed, walk in the statutes of life, without committing iniquity; he shall surely live, he shall not die.

"None of his sins that he hath committed shall be mentioned unto him: he hath done that which is lawful and right; he shall surely live.

"Yet the children of thy people say, The way of the Lord is not equal: [is this where you are at Agnostic?] but as for them, their way is not equal. When the righteous turneth from his righteousness, and committeth iniquity, he shall even die thereby. But if the wicked turn from his wickedness, and do that which is lawful and right, he shall live thereby.

"Yet ye say, The way of the Lord is not equal. O ye house of Israel, I will judge you every one after his ways."

God is not a god of logic. He is a God of relationship. "Trust in the Lord with all your heart, and lean not to your understanding." This is where you will not be able to follow. Also, God is not interested in proving his logic to anyone. He clearly states his ways are higher than our ways and they are foolishness to those who are learned.

Your logic will not lead you to Jesus, nor will it lead me away.

May you come to know Him, He desires to save you.

Pro 8:13 The fear of the LORD is to hate evil: pride, and arrogancy, and the evil way, and the froward mouth, do I hate.
Pro 8:14 Counsel is mine, and sound wisdom: I am understanding; I have strength.
Pro 8:15 By me kings reign, and princes decree justice.
Pro 8:16 By me princes rule, and nobles, even all the judges of the earth.
Pro 8:17 I love them that love me; and those that seek me early shall find me.
Pro 8:18 Riches and honour are with me; yea, durable riches and righteousness.
Pro 8:19 My fruit is better than gold, yea, than fine gold; and my revenue than choice silver.
Pro 8:20 I lead in the way of righteousness, in the midst of the paths of judgment:
Pro 8:21 That I may cause those that love me to inherit substance; and I will fill their treasures.

I would not worry about the children, I would worry about myself, an adult who sat on the fence demanding an answer from the One who is the Judge of the Earth. God is gracious and we may all be surprised at His provision for the children. You are his child, do not hide from Him behind your questions. He wants to bless you.

Tim