Macbook 12" doesn't sleep/wake on close/open
Your power management settings are excellent. If you say you've already reset all of the controllers that could be causing this problem, then it really could be a hardware failure.
I just don't quite understand how you notice that the computer is not sleeping? In the settings of pmset no process prevents sleep?
My final advice would be to switch to Hibernatemode 25
sudo pmset -a hibernatemode 25