Hope this helps:
How could these angels know this? Did Allah ta'ala give them this knowledge? Or were there another creatures, before mankind, who caused mischief and shed blood?
From Tafsir Ibn Kathir explaining this verse:
The angels meant that this type of creature usually commits the atrocities they mentioned. The angels knew of this fact, according to their understanding of human nature, for Allah stated that He would create man from clay. Or, the angels understood this fact from the word Khalifah, which also means the person who judges disputes that occur between people, forbidding them from injustice and sin, as Al-Qurtubi said.
The statement the angels uttered was not a form of disputing with Allah's, nor out of envy for the Children of Adam, as some mistakenly thought. Allah has described them as those who do not precede Him in speaking, meaning that they do not ask Allah anything without His permission. When Allah informed them that He was going to create a creation on the earth, and they had knowledge that this creation would commit mischief on it, as Qatadah mentioned, they said,
أَتَجْعَلُ فِيهَا مَن يُفْسِدُ فِيهَا وَيَسْفِكُ الدِّمَآءَ
Will You place therein those who will make mischief therein and shed blood)
This is only a question for the sake of learning about the wisdom of that, as if they said, Our Lord! What is the wisdom of creating such creatures since they will cause trouble in the earth and spill blood "If the wisdom behind this action is that You be worshipped, we praise and glorify You (meaning we pray to You) we never indulge in mischief, so why create other creatures''
Why does Allah ta'ala call Iblis an angel? As far as I know he is a Jinn! How did Iblis make it to be in a such high position with the angels? Was there a fight between angels and jinns and he become a righteous one?
When Allah commanded the angels to prostrate before Adam, Iblis was included in this command. Although Iblis was not an angel, he was trying - and pretending - to imitate the angels' behavior and deeds, and this is why he was also included in the command to the angels to prostrate before Adam. Satan was criticized for defying that command, as we will explain with detail, Allah willing, when we mention the Tafsir of Allah's statement,
إِلاَّ إِبْلِيسَ كَانَ مِنَ الْجِنِّ فَفَسَقَ عَنْ أَمْرِ رَبِّهِ
(Except Iblis (Satan). He was one of the Jinn; he disobeyed the command of his Lord.) (18:50)
Similarly, Muhammad bin Ishaq reported that Ibn `Abbas said, "Before he undertook the path of sin, Iblis was with the angels and was called `Azazil.' He was among the residents of the earth and was one of the most active worshippers and knowledgeable persons among the angels. This fact caused him to be arrogant. Iblis was from a genus called Jinn.''