Okay, so to follow the time line more closely, let's begin with the "two trees in the Garden" question, first:
In Genesis 2:9, the Bible tells us: Out of the ground ADONAI, God, caused to grow every tree pleasing in apperance and good for food, including the tree of life in the middle of the garden and the tree of knowledge of good and evil.
This indicates that there were, in fact TWO trees. The Bible then goes on to explain what God told Adam:
Genesis 2:15: ADONAI, God, took the person and put him in the garden of 'Eden to cultivate and care for it. 16 ADONAI, God, gave the person this order: "You may freely eat from every tree in the garden 17 except the tree of the knowledge of good and evil. You are not to eat from it, because on the day that you eat from it, it will become certain that you will die."
Now, here's the thing: Because the fruit on God's trees didn't kill humans instantly, we must surmise that the word "die" refers to the pair now "becoming mortal". Until Adam allowed his mate to coax him into "eating the fruit," there was no sin in the world, and the pair already had a LONG life because they weren't clothed with mortal flesh at the time. (Please read our article revealing that the "garments of skin" with which YHWH clothed them, was "human skin.")
We cannot know what all took place at "the beginning," from the time YHWH created the universe and everything in it, up to the day that Adam and Eve sinned. We have no way of knowing how old they were at the time. ALL we can really do is to glean from what was written in the Torah. We learn in Genesis 3:22 (see below) the pair would have become God-like if they had eaten from the tree of life - meaning to become immortal ... something that wasn't supposed to happen during humanity's lifetime ... for reasons known only to YHWH Himself.
We do know that God told them if they ate from the Tree of Knowledge of good and evil, they would become beings that would eventually die. Before eating from either tree, it seems Man was in a kind of "twilight zone" - because the Bible doesn't actually SAY that Adam and Eve were destined to live forever. Maybe they were perched precariously between mortality and immortality, and man's nature was actually undetermined at the time of Adam - which might have bee part of God's overall plan!
If Eden was a place where man was precariously placed between life and death, depending on his choice - then, it would seem that Eden eerily foreshadows other great moments in history when man was neither "here nor there", and the Almighty offered us a similar choice between "life" and "death" - first with Moses in the desert:
Deuteronomy 30: 15 "Look! I am presenting you today with, on one hand, life and good; and on the other, death and evil....
Deuteronomy 30: 19 I call on heaven and earth to witness against you today that I have presented you with life and death, the blessing and the curse. Therefore, choose life....
Bottom line - Adam and Eve eventually physically died because they had sinned. And, unless we "choose life" through Yeshua, our spirits will be condemned to die in the Lake of Fire and we will be eternally separated from God just like we were before man was ever created.
Now, about the "us" God referred to in Genesis 3:
Genesis 3:22 ADONAI, God, said, "See, the man has become like one of us, knowing good and evil. Now, to prevent his putting out his hand and taking also from the tree of life, eating, and living forever --" 23 therefore, ADONAI, God, sent him out of the garden of 'Eden to cultivate the ground from which he was taken.
The "us" Yahweh is talking to is the other parts of Himself - the "Echad" (His plurality - the entities by which He has revealed Himself to us: Father, Son, Ruach, burning bush, pillars of cloud and fire; He revealed Himself as "three men" to Abraham at the Oaks of Mamre, and He's even spoken through a donkey). While some have suggested that Genesis 3:22 means there must be multiple "gods", we know this is not the case from countless other scriptures where YHWH states categorically that He is the ONLY God. (See for example Isaiah 45, verses 5, 6, and 8). We also know that Yeshua was present at the creation (John 1:1-4), so that automatically means "two" were present which makes it possible to say "us" in Genesis 3.22.
We can conclude that the "us" in Genesis 3:22 would not likely include the "angels", because the angels couldn't have been "one of us", as they were created beings. Nevertheless, the angels came about early, probably before man because we find them mentioned in Job:
Job 38:4 "Where were you when I founded the earth? Tell me, if you know so much. 5 Do you know who determined its dimensions or who stretched the measuring line across it? 6 On what were its bases sunk, or who laid its cornerstone, 7 when the morning stars sang together, and all the sons of God shouted for joy?
So clearly, the account of the creation is not intended to be complete in the order of creation of the "entities" present with YHWH at the time. Nevertheless, it seems clear that the "us" in Genesis 3:22 refers only to YHWH, Himself, in His "echad" - whatever comprises Him - and certainly NOT to multiple "gods"!
As to your comment about the completion of the sentence at the end of Genesis 3:22, it really does not require completion. Remember, Moshe is writing this history as a narrative and the text is written to "involve us" in the creation. So, he describes a statement YHWH is speaking, then transitions to the action YHWH took on what He was speaking. It's a permitted literary technique. However, a clue seems to be revealed in the Book of Revelation:
Revelation 22: 14 "Blessed are they who do His commandments, that their authority will be theirs unto the tree of life, and to enter through the gates and into the city."
Following is an excerpt from the appendix entitled "Legalism" in the Aramaic English New Testament, which further examines these issues:
We are introduced to the consequences of breaking "the Law" (Torah) in the beginning of the Bible (Genesis 3) where the very first case of blatant disobedience occurred - an act that impacted the children of Adam and Eve and every single generation of man since then! Because of that one act of disobedience, man has been "born into sin" ever since; constantly forced to battle the wiles of the Evil One and facing possible eternal separation from YHWH. Before sin, Adam and Eve were clothed in righteousness (the Light of Mashiyach); but haSatan exposed their nakedness through guilt, shame and condemnation.
Guilt (which results from wrong-doing is spiritual separation), is a function of the Ruach haKodesh; it is a spiritual force that motivates us to make it right with YHWH and one another. The guilty parties - not knowing whether they will be forgiven their transgression until they confess and present their case - feel sorrow, emptiness, depression and despair for breaking faith and violating the peace and harmony of Mashiyach. The shame that Adam and Eve experienced was compounded in the knowledge that their sin had been preventable, and that they had needlessly and willingly exposed themselves to a difficult situation that caused them to risk everything without considering the consequences.
The curses against Adam and Eve became part of universal natural law that applies to all inhabitants of the Earth. "Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever..." (Genesis 3:22). Man was formerly a sinless and immortal being who became as the angelic host to know good and evil (many believe that the angelic war between good and evil is what spawned the creation of mankind); therefore, YHWH provided redemption through death and resurrection. The plan of redemption is this Good News that Mashiyach demonstrated through his resurrection as the "Firstfruits" of all Creation. Mankind has always been sustained according to the Word of YHWH, "For YHWH is our judge, YHWH is our lawgiver, YHWH is our king; He will save us." (Isaiah 33:22).
The thing is also: If man gets too much knowledge (as he already has - and just look at some of the BAD that has come of it because it's been abused by many), then man will be like the angel Lucifer was, and try to become God. It's our sin nature to be dominant. (If you ask people such as the Scientologists - the religion that the Hollywood crowd is enamored with - man is already God!) That, naturally, can only lead to a complete downfall along with total destruction of mankind - especially, in view of the fact that God's ultimate goal is to have man live with Him in eternity....
Yahweh's ultimate goal, also, was to have the wayward mankind coming to Him through FAITH. That's why He sent Yeshua who made it easy for us to gain eternal life. He did not "rape" us or brow-beat us into submission; He gives each of us the choice to come to Him willingly or not at all. He gave us the Bible and everything we need to know in order to get to heaven. What we do, however, is OUR choice. Consequently, we either go to heaven or hell. We've had plenty of warning from our Creator!