I appreciate all the effort in analyzing the passage. Sometimes, I think we make it too complicated.
Jesus is responding to the Pharisees and scribes who did not believe He should associate with "sinners". We don't have to place the labels of "saved" or "unsaved" on either son. That wasn't the focus or the point of the parable.
The point is that God rejoices when sinners repent. God embraces sinners who repent. The Pharisees and scribes would not and did not. We don't have to go any further than that.
The application that comes to our churches is how do we respond when people are saved? Do we rejoice? What about people that don't look like us? What about people living in different economic conditions than we do?
If someone with tattos and piercings and multi-colored hair were saved, would you welcome them into the fellowship? What about a crack addicted prostitute? Would you rejoice that God had sent that person to your fellowship? A thief? A hardened criminal? A homerse*ual? A minority? A mixed race couple with 5 children and living on Social Security disability?
Do we really welcome and rejoice in the salvation of those people, just as God does? Or do we quietly hope that God will fill our congregations with 1000's of middle and upper-middle class professional families that will fund our programs and volunteer for our committees and complete our own "network"?
God rejoices when sinners (even those coming straight from a pig-pen) repent and so should we.
peace to you

raying: