So -- all those spirit children were up there somewhere before humans came into existence.
Let's talk about all those spirit children another way.
In Genesis 1:26-27 it says God said, let US create man in our image and in our likeness and so he did, male and female created he them.
1) where did God create man, male and female?
2) how many male and female did God create at this time?
Then we read in Genesis 2:5 that there was not a man on the earth yet?
1) wait a minute, did I not read in Geneses 1:26-27 that God created man, male and female already?
a) again, if there is no man on the earth, where did God create man, male and female in Gen. 1?
Then we read in Genesis 2:7 that God created a man, Adam out of the dust of the ground?
1) Wait a minute, who were the male and female created in Gen. 1:26-27? Where were they created, because it was certainly not on earth? How many of them were created?
The Church of Jesus Christ can answer those questions. In Genesis 1, God/Elohim + others created man, male and female in heaven before they were naturally created on earth in Genesis 2. Genesis 2:5 confirms that by letting us know that after the creation in 1, there was no man on the earth yet. So where did the creation in Gen. 1 take place: in heaven.
So where did the creation of Adam and Eve in Gen. 2 take place: on earth.
So who created Adam and Eve on earth. As it says in Genesis 2:4? It was the "Lord God", but not God as in Genesis 1. The "Lord God" is Yahweh or Jehovah which eventually was incarnated into the flesh body of Jesus. Who we know created all things (naturally).
It is unknown how long it was between the spirit creation in heaven and the natural creation on earth. Long enough for Jesus to show God that he too remained sinless from the beginning, and for God the Father to call him God the Son.
(see Hebrews 1:8-10, Psalms 110:1)
Man, male and female was created in heaven in a spirit body, and over thousands of years, these spirit bodies have systematically been placed into flesh bodies on earth. Adam was the first man to receive his spirit body into his flesh body. Eve was the first female to receive her spirit body into her flesh body.
You and I had to wait about 6,000 years for our spirit bodies to be placed in our flesh bodies.
Able was the first person to die on the earth. He was the first to experience his spirit body leaving his flesh body and going into the "spirit dwelling place". By this time there are billions of spirit bodies in the "spirit dwelling place". (I could tell you a lot more about what happens in the "spirit dwelling place", but not the time. Just to say, they are all awaiting the time of the resurrection when the spirit body and the flesh body will be reunited and be inseparable for eternity. That is why you will be immortal, because your eternal spirit body that gives life to your flesh body will never again be separated, and you will live forever, hopefully living with God and Jesus in their kingdom.
-why would they have had to become spirit children if they were already some sort of intelligence?
Spirit is matter, just refined matter. Intelligence is something different - we know very little about our intelligence. In order for the intelligence to be something, it needed to be housed in the spirit that is something with mass. I know that sounds odd, but again, we know very little at this point about the make up of this intelligence/or the mind and will of man.
So the first step toward being like God was for God to take this uncreated, eternal intelligence (whatever it is) and place it in our uncreated, eternal spirit, which now, together comprise an independent entity with a mind and will and a body of refined matter. Now able to communicate, and to act upon and be acted upon. It is this acting upon and being acted upon that increases the already existing intelligence that is necessary for us to grow and become something greater than we are. God knows this process and gives us every opportunity to move forward, hoping that we will eventually become just like he is and live with him as he is.
This is the whole purpose of God: to bring to pass the immortality and eternal life of man. It is a long process, and all along the way man has to make choices, and many are lost and disqualify themselves from reaching the ultimate goal. But many will keep making the right choices, and qualifying themselves for the highest glory possible, life with God and Jesus.
The first choice was in the pre-earth life between following Jesus and following lucifer. It is said in
Jude 1:6 that many kept not their first estate(actually 1/3 of the spirit children of God) but chose to follow lucifer and immediately disqualified themselves for even mortality, and not chance for eternal life. You and I did keep our first estate, and we are now in our second estate. If we choose Jesus again in this estate, where we are fallen outside the presence of God and in the presence of satan and his followers, we will receive eternal life in an incredible, perfect, highly mobile body of flesh and bone and spirit just like God and Jesus, and will be doing the same kinds of things that they do. The ultimate goal.