I think a good portion of those questions can be answered by Romans 5:12-19.
Discussion
I read the verses, thanks for sharing but I don’t understand. Adam brought sin into the world and Jesus takes away sin but my question is God made Adam and Jesus, why are they not brothers since they are both of his creation. Adam was a man and Jesus was a man once. Is what separates them sin?
"They were both created by God."
Not so much. Jesus is fully man and fully God, co-eternal with the Father. His humanity had a starting point, but his divinity does not.
"In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things were made through him, and without him was not any thing made that was made. 4 In him was life, and the life was the light of men." John 1:1-4
So, Adam cannot be Jesus' brother, because Jesus is Adam's creator, which also explains one reason Jesus is more important than Adam. The fact that Jesus willingly took on himself the sins of his people in order to redeem them, while Adam only passed his sin on to his posterity is another massive reason.