Hi wildwillow,
So I have both of my monitors working together by adding patches to my config.plist (10.11-SKL-1912000-4_displays, 10.11.4-SKL-Port_0x6-DP2DVI, and 10.11.4-SKL-Port_0x5-DP2HDMI.) However, I have run into problems. When I turn off a single monitor displaying macOS and later turn it back on, that monitor goes green or black. I have another related problem, when I switch to a different device, PS4, then back to macOS using an HDMI switch, the switched monitor goes black and the one that was displaying macOS the whole time turns green. Basically I can't turn off the monitors or use an HDMI switch. The only way dual monitors work for me, is to leave both on all the time and never switch the one connected to an HDMI switch away and back to macOS. Can you help me?