Your first sentence is where you are first getting off track. A sacrifice didn't need all that you outlined here. A sacrifice was a gift to God to show thanks. If Jesus was murdered at the age of 2 or younger people would then not believe it was Jesus because a imposter could stand in. Also Jesus's teaching was original moral teaching. When other at that period of time did somebody step in to save a person from being stoned? Also as the people knew Jesus as an adult when He arose from the grave He was reconizable as Himself. This would not be possable if He was killed as a child.
First, you are correct about many aspects of acceptable sacrifice. However, what you miss is that scripture records Jesus' actions as being more than on earth. However, I will first address your idea of "child sacrifice".
Jesus could not have been sacrificed at 2 because it wouldn't have been just. Jesus' puropose wasn't simply in His death, it was in His life. There had never been a person before Him who had existed without sinning. Yes, Jesus had not sinned at two; however, He was not an adult. Does a two-year-old face the same temptations as a 33-year-old? Absolutely not.
Second, pagan soldiers did not kill Jesus,
it was Caiaphas, the high priest who fought to have him killed, although Roman soldiers carried out the crucifiction upon the command of Pontius Pilate. However, the action of the high priest was merely symbolic Jesus said "I lay down my life, that I might take it again. No man taketh it from me, but I lay it down of myself."
A Messianic passage in Psalms says Meschiach will be a priest after the order of Melchizedek, an ancient One who appeared to Abraham. By His description in different passages many believe Him to be God.
1. If Jesus is a priest, and He sacrificed Himself, this fulfilled the high priest requirement for sacrifice.
2. Before the crucifiction, Jesus was whipped with a cat of nine tails an instrument of glass and broken shards and leather. This toture device would indeed rip open the body and entrails would spill out. At the time of Jesus' death on the cross His entrails would have been hanging out and probably on the cross--His wooden altar.
3. As afore stated Jesus did not complete His work on earth He also went to hell and preached to souls who were there and as many as would come, rose with Him (I Peter). Jesus also told Mary Magdelene that she could not touch Him because He hadn't yet ascended to the Father. The sacrifice was not yet complete, many believe, through study, to mean that Jesus' sacrifice was not yet finished, and He also sprinkled His own blood upon an altar in heaven.
4. Paul said in 1 Corinthians 15:56 "the sting of death is sin". The "sting" being the power, death has no power over the sinless, Jesus submitted Himself to death in order to effectively eradicate its claim on mankind. Those who accept Jesus' Acts 2:38 flight out only experience sleep. (See henrietta lax).
5. Jesus therefore fulfilled the law and the prophets in His birth, life and death.