Mammon represents the worldly wealth, the actual money, contrary to the true riches (Luke 16:11), the eternal dwellings.
Jesus used the Parable of the Shrewd Manager to teach His disciples, even the son of the world know best how to use money for his own good, they should use the worldly wealth wisely for their eternal dwellings. Jesus concluded His teaching "You cannot serve both God and money", so let go the worldly wealth and serving God.
There is no contradiction of Luke 16:9 & 16:13. Jesus' message is clear: give away the worldly wealth (mammon) in order to earn the eternal dwellings. You either have God's wealth (eternal dwellings) or worldly wealth (mammon) but not both.
The friends who will receive you into eternal dwellings is Jesus (Luke 16:9). So when His disciples do what Jesus commanded, give away the worldly wealth for one of the least of brothers and sisters of Jesus, they did for Jesus, and Jesus will receive them into eternal dwellings.
37 “Then the righteous will answer him, ‘Lord, when did we see you hungry and feed you, or thirsty and give you something to drink? 38 When did we see you a stranger and invite you in, or needing clothes and clothe you? 39 When did we see you sick or in prison and go to visit you?’ 40 “The King will reply, ‘Truly I tell you, whatever you did for one of the least of these brothers and sisters of mine, you did for me.’ (Matthew 25:37-40 NIV)
14 You are my friends if you do what I command. 15 I no longer call you servants, because a servant does not know his master’s business. Instead, I have called you friends, for everything that I learned from my Father I have made known to you. (John 15:14-15 NIV)
"In Luke 16, Jesus appears to imply "Mammon" is both positive, and negative. How should the contradiction be resolved?"B.) Is my edit a proper representation of your intent? C.) Also, I *just* posted a very related question : How should “Mammon” be Interpreted - Linguistically? – elika kohen Mar 09 '17 at 01:48