You raise some great questions
...ones I asked myself before I really studied the Bible apart from Christendom's teachings. The church could never answer those questions satisfactorily. I went searching for answers that made sense and were from God's word.
I came to see that there is a spiritual being who is the Creator of everything. He has immense power than emanates from him to accomplish his will. That power is God's holy spirit. It is the exercise or implementation of God's power, but it is not a person, nor is it God. It itself empowers others....even sinful humans.
God does not have a physical body, but it seems as if he has a spiritual body that is immaterial. No one has ever seen him apart from spirit beings. (John 5:37) No one can. (Col 1:15)
Before coming to be born as a human, Jesus too possessed a spirit body. The person of God's firstborn son was somehow transferred into the womb of a Jewish maiden and brought to birth just like any other human.....but this person had lived before, in another realm, for eons of time. He was unique, but he was fully human...and completely mortal.
Since the Bible tells us that God is immortal, there is no way that Jesus could be both "fully God and fully man". Immortals cannot die, and mortals cannot kill God.
Spirit beings in the Bible at times manifested themselves in material bodies of flesh. They ate and drank and spoke with God's human servants, then when their mission was accomplished, they simply dematerialized and returned to the spirit realm....a realm no human can fully explain since none of us have ever been there. The body that Jesus was raised in was spiritual, he too had the power to materialize and dematerialize at will, hence his ability to appear to his disciples and disappear before their eyes.
Jesus could not just materialize a human body to accomplish his role as redeemer because he had to be a son of Adam to pay the ransom price demanded under the law. (1 Cor 15:45)
Yep, a somewhat concise description of what most in Christendom believe. It has snatches of truth but is inaccurate in its overall presentation however.
To understand why Jesus was sent to die, you must first understand the concept of atonement or redemption. In the Law of Moses, a person could be sold into slavery to cover a debt. A relative or other person could redeem that person and free them from slavery if they paid his debt in full. Atonement is literally "at-one-ment", meaning that something of an equivalent value was handed over. In the case of Jesus, Adam lost perfect sinless life for all his children, so in order to redeem them, God sent one whose life was the equivalent of what Adam lost. A sinless life was offered for a sinless life. Since all of Adam's children now had the defect of sin, there was no one among them to pay the price and free them from slavery to sin and death. Hence a sinless life had to come from outside the now defective human race.
In the Bible Jesus is called "the last Adam" because he atones for what Adam forfeited for his children. Adam himself paid for his sin with his own life, but Jesus rescued his children by voluntarily offering his own life for them. It was not their fault and God made the way to rectify the situation whilst keeping his perfect law.
LOL...nicely stated...you hit the dilemma right on the head.
The only thing I will pick out of that is that God knew that a bad spirit would corrupt his creation. I believe that God can know whatever he wants, but that when he created free willed creatures, he did not want micro-manage their actions. What he did was state penalties for certain actions and warn them not to transgress.
We are told in the scriptures that we will "reap what we have sown"....even if we initially didn't intend to do the wrong thing. If you plant carrots and then change your mind, beets won't come up. Carrots is what you will have to eat. Free will is ours to exercise, even in a bad way. It tells God who we are and when he exercises his power in the future to bring all things back to square one, he will have chosen the citizens of his kingdom without having to force them to do anything. They will all be obedient to their Father out of love for him and appreciation for his wisdom in separating humans for life or death. There is no heaven or hell, there is just the natural result of the exercise of God's perfect justice.
That puts the onus right back onto our shoulders. We are the captain of our own ship...we drive it, and no one else, so we can't shift the blame to others or even the devil when we give in to sin. No one can force us to do anything against our will....not even our Creator. And the thing is...he doesn't want to. He wants obedience to come from the heart as we trust him to know what he's doing and to keep us informed about his intentions towards this earth and all who inhabit it.
The future is looking bleak from a human standpoint but from the Christian view, everything is right on schedule. The "last days" will come to their end, mankind will be judged as either worthy or unworthy of everlasting life, right here on planet Earth, and we can all get on with what God originally intended for this vast universe....the sky is literally the limit.