Do you really want to get into the lie that is the theory of evolution.  Even Darwin did not fully believe it.  Or do you want to go into the type of morality that the idea of evolution leads us to.  
As far as the existence of Jesus, there is more historical record of Him, than almost anybody else from his time period.   Also, you say He may have started out as a good man and progressed.   How was that when He claimed to be the son of God at age 12?   You have heard the story of Him being left behind on a trip to Jerusalem for the Passover feast.   When his parents miss him and go looking for Him, they find him at the Temple, and He makes this statement, "Why were you searching for me?  Did you not know that I had to be in my Father's house?".   Since the Temple was known to be God's house, He was calling himself the son of God.   This was at age 12.   So, what was He at age 12?  A good boy, a liar, or a lunatic?  Does a good boy call himself the son of God?