Because in this case he would have known all along that some of his angels wouldn't be thrilled with humans and Lucifer and co. couldn't have rebelled in the first place.

Unless, of course, that was exactly what God planned. But in that case, humans would probably still have as much free will as angels.

Well, why would Lucifer be God's Adversary if he is second to Michael as well?

Did they say that Michael was more powerful than Lucifer? *iz confused* Does "first" actually refer to his age exclusively?