If I have to pick one thing at a time, I'm going to ask again for you to give me the exact verse(s) where slavery is abolished.
First of all how do people acquire slaves? It is not something that most people will allow to themselves willingly. Slaves are usually acquired by war or being forcibly captured. Either by pirates, smugglers or bandits.
The Islamic sects mostly relied on prisoners of war for slavery although sometimes slaves were captured by bandits and slave traders and traded off.
Also slavery requires a legal framework whereby a person can own another human being. This requires some legal framework. In the US it was racially based whereby the law allowed Whites to won Blacks as slaves in the belief that Blacks are inferior species to Blacks. Whites could not be taken as slaves. There were many Whites taken as slaves such as the Ottoman Empire which relied heavily on Easter European slaves. The legal framework established by Sunni Islam is that only a non Muslim can be taken as slaves. Usually once again this can be acquired during war. There are hadiths that allow that.
The Quran only gave two options for prisoners of war. Freedom or ransom. It also ordered the believers in many occasions to free the slaves. Not just not engage in slavery but to actively to everything possible to free the slaves. The Quran placed freeing of slaves in the same category as feeding the poor. Many times the Quran warned mankind that those who refuse to feed the poor and spend from what God gave them for the less fortunate will face God's retribution on judgement day.
2.177 Righteousness is not that you turn your faces toward the east or the west, but [true] righteousness is [in] one who believes in Allah , the Last Day, the angels, the Book, and the prophets and gives wealth, in spite of love for it, to relatives, orphans, the needy, the traveler, those who ask [for help],
and for freeing slaves; [and who] establishes prayer and gives zakah; [those who] fulfill their promise when they promise; and [those who] are patient in poverty and hardship and during battle. Those are the ones who have been true, and it is those who are the righteous.
Did we not show him the two paths? He should choose the difficult path. Which one is the difficult path?
The freeing of slaves. Feeding, during the time of hardship... [90:10-14]
The charities are to go to the poor, and the needy, and those who work to collect them, and those whose hearts have been united,
and to free the slaves, and those in debt, and in the cause of God, and the traveller. A duty from God, and God is Knowledgeable, Wise. [9:60]
Now the Quran gave only two options for prisoners of war.
Therefore, if you encounter those who deny the truth (in warfare), then bring about the captives until when you have subdued/overcome them, then strengthen the bind.
Then after either grace/favour or ransom, until the war lays down its burdens. That, and had God willed, surely He would have gained victory Himself from them, but He tests some of you with others. And those who get killed in the cause of God, He will never let their deeds be put to waste. [47:4]
76. 8-10
And feed with food the needy wretch, the orphan and the prisoner, for love of Him.
(Saying): We feed you, for the sake of Allah only. We wish for no reward nor thanks from you; Lo! we fear from our Lord a day of frowning and of fate.
We are also told in the Quran that slavery was one of accusation levied by Moses against the Pharaoh whom the Quran describes as a tyrant.
Moses said: "I did it then, when I was an ignorant (as regards my Lord and His Message). So I fled from you when I feared you. But my Lord has granted me right judgments of the affairs and Prophethood, and appointed me as one of the Messengers.
And this is the past favor with which you reproach me, and that you have enslaved the children of Israel." 26. 16 - 18
As far as racial supremacy we are told in the Quran:
O mankind, indeed We have created you from male and female
and made you peoples and tribes that you may know one another. Indeed, the most noble of you in the sight of Allah is the most righteous of you. Indeed, Allah is Knowing and Acquainted. 49. 13
And of His signs is the creation of the heavens and the earth
and the diversity of your languages and your colors. Indeed in that are signs for those of knowledge. 30.22
And one of His signs is the creation of the heavens and the earth
and the diversity of your tongues and colors; most surely there are signs in this for the learned.
So there is no way to establish a legalized slavery system in a Quranic nation since believers are ordered in the Quran to free the salves owned by others.
God can not order someone to feed the poor and the needy and to free the slaves and then allow you to own slaves at the same time. That is like saying God orders to feed the poor but allows you to starve someone at the same time.
So it is not enough to just say we are not to take slaves. We are also to do whatever we can to free slaves and abolish slavery whenever and however we can. The Quran does not believe in racial superiority and does not believe in enslaving prisoners and does not believe in a laissez faire attitude about slavery also.