I have it working with two DP monitors and the laptop screen. But this only works in XFCE not Unity, even though I use lightdm with XFCE. Optimus actually probably would have worked out of the box except that I added a brightness control xorg.conf tweak which broke Optimus (the problem with 2011 hardware is a lot of neolithic advice). With 16.04.2's 4.8 kernel and Nvidia 367 driver that tweak isn't necessary anyway.