I like many of your claims in this post regarding God as a unity of three personal relations: Fatherhood, Sonhood and Love.
You address a number of interesting queries regarding angels, which are worthy to be further discussed:
The fact that some angels rebelled against God whereas most of them accepted to worship him, is a clear sign that angels have free will.
On the one hand we know that God is keen to redeem sinners to the end of incarnating Himself and dying on the cross. On the other hand we know that He is almighty. So your question is quite pertinent: Why then did God not foresee Redemption for the fallen angels?
The only possible answer seems to be that angels reject to be saved so that God would have to violate their free will in order to save them. But God cannot do such a violation because it would mean that God contradicts himself, what is absurd.
This point can be better understood through a comparison with “opiate addiction”: The more consumption, the more difficult to overcome the addiction. The reason is that the addict makes himself a wrong idea about how to reach happiness and adheres more and more to it, till at the end it clings immovably to it.
Sinning is sort of addiction: The more someone sins, the more he reinforces his own will in rejecting God, and the less is he willing to convert. For humans death is nothing other than the moment where the own will clings immovably forever to love God or reject Him.
Now angels are pure spirits and this means that an angel does not make up his mind in several successive steps but decides once and for all. If an angel rejects God he remains “addicted” to this decision forever.
God is also a pure spiritual being who thinks and act.
Humans themselves think and freely act because they are incarnate spirits. Angels are far more powerful in thinking and acting than we humans are.
Only incarnate spirits like humans can die: Angels have no body and therefore cannot die.
However there are also humans who did not die: Remember for instance Melchizedek!
Notice that spiritual beings cannot be annihilated: As well angels (pure spirits) as humans (incarnate spirits) have never ending existence.
Through creation God aims that a hug number of spiritual creatures reach happiness by freely sharing in His love.
The perfection of creation requires that God primarily created pure spirits (angels). Nonetheless a number of them sinned and let a number of places in “the kingdom of heaven” unoccupied. So God foresaw to create humans, that is, incarnate spirits living in time, who are called to fill the places in heaven that remained vacant because of the angel’s fall. Human history will go on till all the places in the “banquet of the kingdom of heaven” are filled.
Neither angels not humans are essential to God.
As discussed in the thread “My theory about the Flood”, in Scripture the term “sons of God” refers to creatures who were created by God independently of any creature’s will (i.e.: without parents). So the term may refer to angels, like in Job 1:6, but also to humans, like in Genesis 6:2-4. In the latter case God created these “sons of God” the same way He created Adam, that is, by transforming Homo sapiens individuals into humans endowed with free will and therefore capable of sinning.
Jesus Christ himself and the New Testament unambiguously speak about angels and Satan.
If you dispose of angels, you dispose of “Satan and his angels” as well.