I actually didn't receive notification about this thread, though I was obviously tagged. I just stumbled across it.
The answers to your questions are simple, though you do have some erroneous assumptions that lead to faulty conclusions.
Let's see if you may receive the help you need.
1. Numbers 23:19 KJB is in the immediate context of Numbers 23:13-26 KJB known as the 2nd oracle of Balaam the prophet of madness (2 Peter 2:16 KJB).
Consider that Numbers 23:19 KJB comes immediately after Balaam begins his prophetic "parable" (Numbers 23:18 KJB), which, by the way, uses proper names (so much for that myth that parables cannot or do not use or have proper names, ie Luke 16).
2. The text does not say, "God is not a man (full stop)" with period. To say so takes the phrase out of context which is what a devil would do (Matthew 4:6; Luke 4:10-11 KJB).
The text actually says in full:
Num 23:19 KJB: "God is not a man, that he should lie; neither the son of man, that he should repent: hath he said, and shall he not do it? or hath he spoken, and shall he not make it good?"
This is in response to Balak's request to curse Israel (after the flesh) by Balaam. However, God told Balaam to bless Israel, because:
Num 23:21: "He hath not beheld iniquity in Jacob, neither hath he seen perverseness in Israel: the LORD his God is with him, and the shout of a king is among them."
So God promised to bless them as long as they obeyed Him. The people were, up to this point obedient. God, then, as Balaam says, cannot lie, or go back on his word as mankind often does.
The text does not say that God could not (or would not) become a man later, for that was promised since Genesis 3:15,21 KJB. Even mother Eve (Genesis 3:20 KJB) expected Cain to be the Messiah promised (Genesis 4:1 KJB). The people knew about the promise of "Shiloh" (Genesis 49:10 KJB). Abraham and Isaac was even a type enacted in life:
Gen 22:8: "And Abraham said, My son, God will provide himself a lamb for a burnt offering: so they went both of them together."
God (JEHOVAH, the Ancient of Days) did indeed "provide himself a lamb", giving up His own eternal Son.
God (JEHOVAH jr., Jesus) did indeed "provide himself", offering himself, being the "Lamb".
The eternal Father would sacrifice His own eternal Son. Moses knew of this, and even wrote of it by inspiration of the Holy Ghost.
The whole argument that the text says that "God is not a man (full stop)" originated in Arian heresy, such as Islamic dawah-ists, WTS/JW, etc. It's simply a lie, fabricated and disingenuous with the text.
3. The phrase "only begotten" (John 1:14,18, 3:16,18; Hebrews 11:17; 1 John 4:9 KJB), is basically monogene (μονογενῆ; John 3:16; Hebrews 11:17; 1 John 4:9) or monogenes (μονογενὴς; John 1:18) or monogenous (μονογενοῦς; John 1:14, 3:18) and in context refers to the Son's eternal nature as Deity, being the only one of the same nature as His Father (Philippians 2:5-7 KJB, "form of God" (nature of Deity) in contrast to "form of a servant" (nature of mankind); and Hebrews 1:3, "the express image" (of the eternal Father)). Mono means only, or singular, even one. Genes, refers to nature, not birth or coming into existence. Mono - Gene, simply means in context "the only one that shares the same nature as the Father". Jesus is the original Heir of the Father by nature (being eternal Deity in nature as His Father is). The other "sons", like the created heavenly angelic hosts (like Gabriel and 'herald', etc) are not of the same eternal nature as the Father and Son. Those angelic hosts have their own created flesh nature's (1 Corinthians 15:35-45; Hebrews 2:16; Jude 1:7 KJB) which differs from God's eternal flesh nature and mankind's flesh nature. They are "sons" by creation. Mankind, in a similar, though slightly differing fashion, are also "sons" by creation (at the first, in Adam), but now adopted by redemption (Romans 8:15; Galatians 4:6 KJB). They are all "sons", but Jesus is the only "son" by original eternal nature of the Father. This is why the Father is called "the only 'true' God" (means underived and original nature) and the Son is the "only begotten" (derives the eternal nature from or) of the Father. In other words the word 'true' simply means that the Father's eternal nature is original with Himself, while the Son derives that nature by the Father. This is what makes them eternal Father and eternal Son.
This does not mean that the Father is, or ever was 'human'. The Son, in Philippians 2 took on an additional nature (mankind's flesh nature) to the original eternal nature He always had (Deity's nature).
4. The phrases found in Malachi 3:6; Psalms 102:12,24-27; Hebrews 1:8-12, 13:6-8, etc, is speaking about the eternal and unchanging character of Deity. The heart of Deity.
Mal 3:6: "For I am the LORD, I change not; therefore ye sons of Jacob are not consumed."
In other words, the texts are not saying that Deity could not become clothed with the nature of mankind, as the Son mysteriously did. They are stating, in context (the name of God - JEHOVAH, see Exodus 33:12-23, 34:1-9, 20:5-7 KJB, as his name is, so is he), that God's heart, the eternal character of love does not ever change and that is the reason that the "sons of Jacob (supplanters, decievers, fallen by iniquity)" are therefore "not consumed" because of the unchanging and eternal character of mercy, compassion, forgiveness, justice, etc.
While the Son (eternally in the "form of God"), when taking upon Himself the "form of a servant" (nature of mankind in flesh) chose not to utilize the powers of Deity, did not lay aside, did not change, His eternal character of self-sacrificing love.
The same arguments that were presented in the OP, are a misuse of the texts, and again stem from Arian heresies, such as Islamic Dawahists, WTS/JW, etc. I understand that the OP is simply asking about these failed and silly arguments and do not place any blame upon them for these ridiculous arguments. They simply do not know the scriptures, neither the power of God, for they deny what is written:
1Tim 3:16: "And without controversy great is the mystery of godliness: God was manifest in the flesh, justified in the Spirit, seen of angels, preached unto the Gentiles, believed on in the world, received up into glory."
Real scripture cannot be broken (John 10:35 KJB).
Ps. The ESV, NKJV, NLT are all terribly bad with mistakes in them and are broken in places. They may contain parts of the word of God, in and of themselves are not the whole word of God, demonstrable upon request.
