This is my View on this
I always thought that God needed a Satan to gives us free choice to choose good or evil ------My thoughts on this subject have changed sine I have done some research on Who created Satan ------
To answer your OP question ----So who lived here first? Humans or Satan?
The Scripture says that God created Humans on the last day ---all was in place for Adam and Eve in the Garden ---so for me the Angels were created before Humans -----Lucifer became Satan ----
Now this is what I have come to Spiritually discern by and through The Holy Spirit about Lucifer who turned into Satan ------This is now What I personally believe ----
All angels have free will to choose to obey God or not like we do ---- ------ verse 6
Jude 5-6 (TLB)
5 My answer to them is: Remember this fact—which you know already—that the Lord saved a whole nation of people out of the land of Egypt and then killed every one of them who did not trust and obey him. 6
And I remind you of those angels who were once pure and holy but turned to a life of sin. Now God has them chained up in prisons of darkness, waiting for the judgment day.
Angels can choose to fall into sin as well-----
2 Peter 2 GW
----4 God didn’t spare angels who sinned. He threw them into hell, where he has secured them with chains of darkness and is holding them for judgment.
God created Eden and all that was in it ----including Humans ---God said that it was very good
Genesis 1:31 (GW)
31 And God saw everything that he had made
and that it was very good. There was evening, then morning—the sixth day.
So if Satan was already in the Garden --God would not have said that it was all very good -----So this is what I have come to understand for me ---Lucifer was in the Garden and I believe he was there to Bless Adam and Eve and minister to them by God authority ----it makes no sence to me now that God would create a Satan and put him in the garden to deceive now from what I have studied ----that goes against all that God stands for in my view ---
Ezekiel 28 --to me is prophesying the down fall of Lucifer and refers to in my view
---if this scripture is referring to a human King --then I believe it addresses the Spirit behind this King -who then would be Satan ----which would make prefect sense to tie the 2 together ----
Ezekiel 28 verses 13 GW ---
13
You were in Eden, God’s garden.
You were covered with every kind of precious stone:
red quartz, topaz, crystal,
beryl, onyx, gray quartz, sapphire,
turquoise, and emerald.
Your settings and your sockets
were made of gold when you were created.
This verse to me describes Lucifer ------who was in the Garden ----there was no human King of Tyre in the Garden of Eden that is for sure ---if you read more on the city of Tyre it was full of religious idolatry and immoral sex ----so if the King here is human Satan is the Spirit behind the motivation of this King ----in my view
I personally believe that Lucifer's transgression happened in the garden ----not in heaven
Ezekiel 28:14-15 --- NKJ
14
“You were the anointed cherub who covers;
I established you;
You were on the holy mountain of God;
You walked back and forth in the midst of fiery stones.
15
You were perfect in your ways from the day you were created,
Till iniquity was found in you.
I personally believe that Lucifer understood that when God spoke it because so and when a Covenant is made God would never break it -----and when God gave Adam and Eve total dominion over this earth ---I believe that is when Lucifer became envious and wanted to rule like God and become bigger than God ----at that moment that pride and envy took over he because Satan -----and was in the Garden at that time ---he was not in heaven and kicked down to earth as I originally thought ---I believe now that he became Satan while in Eden ----and thought if he could tempt the 2 to disobey God he would gain control over this earth ----and was not allowed back into God's Holy Place ----and I believe some of the angles made a decision of their free will to join Satan ---I believe Lucifer lost his angelic power the minute he transgressed against God ---
Isaiah 14 verses 12-14 GW ---to me describe WHY Lucifer became Satan ----
12 How you have fallen from heaven, you morning star, son of the dawn!
How you have been cut down to the ground, you conqueror of nations!
13
You thought,
“I’ll go up to heaven and set up my throne above God’s stars.
I’ll sit on the mountain far away in the north
where the gods assemble.
14 I’ll go above the top of the clouds.
I’ll be like the Most High.”
So in my view I see ----Lucifer made himself Satan by wanting to be God ----pride - greed and envy turned a beloved Cherub Angel into an evil Satan --
This is just how I personally see it Now ----and for me it makes perfect sense ----others may disagree --