I will admit that the "life happens" is too simplistic.
But, while I like your synopsis of the book, let's take a slightly different look at it. The following represents a more modern version of how the discussion between God and Satan might have gone (you need a kind of Bill Cosby thinking for it):
SATAN: Hey dude. I note that you've got all these people worshiping you by giving them lots of stuff and protecting them from problems. I bet they wouldn't be so loving and loyal if you took away their protection and they lost it all.
GOD: First, stop with the "dude" stuff. That you rebelled and I didn't just terminate you should be enough. . . . You are probably right about some of them. But I'm confident that Job would not do that.
SATAN: Really? He's one of the richest men around. I bet it wouldn't take very much for him to sing a different tune.
GOD: You're on. His life must be spared.
NARRATOR: Time passes and Job loses a bunch of his stuff. But he remains faithful.
GOD: See what I told you?
SATAN: Double or nothin'. We didn't make it hard enough. Take away everything . . . except his wife. She'll nag the Hell into him. And we should give him some really horrible disease.
GOD. Done.
If we think that Job learned more about God, that is a terribly safe statement. But outside of the little bit that Job says on his own part, this is not a major thing.
So it is hard to insist that "Job reveals" what is virtually hidden in the closet. The account does not really comment on that or point at it. It is not like Job spent a bunch of time developing character. Rather, he managed not to break character and still managed to get a bit of a chewing on. Of course he would respond positively to God's words. He was the most righteous man in the vicinity. And any of us would be impressed if God actually came and spoke directly to us. Not belittling his response.
Besides, if Job reveals how God "builds" a man, then there aren't too many "built" men. ("If that is your definition of an accomplished woman, I daresay that I'm surprised at your knowing any such women." Elizabeth Bennet, Pride and Prejudice.) Few of us ever have the pleasure of receiving 1/4 of the circumstances that Job did, therefore could never hope for much building if that is the way it happens. I think Paul discussed it much better in more than one place. "All things work for good" is only one possible source of such a teaching. Those are much more recognizable to the ordinary person. We really don't have any idea how to comprehend losing your children, servants, animals, and production from your land, followed by a round of leprosy that would spell the end for most. It is too far beyond our experience to be of much meaning. The more likely result of taking Job as the revelation of God building man would be "I like myself the way I am, thank you." I think Job would agree if given the opportunity to chime-in about what was about to befall him prior to it happening. Or even after for that matter.
But you still have not provided what I see as a basis for accepting that God reveals how he builds man (a man?) in Job. You have covered a lot of stuff. But not really dealt with the question. I'm not saying that you can't read it any way you want. Or that it is not possible that it could be used as an example of God using circumstances. But the "build" part is so obscure that I find it difficult to impossible to see.