Vega-56 only outputting to 2 monitors

Hi there!
I had been encountering random hard locks with my machine for a while. A fantastic user by the name of Box was kind enough to help me on discord today to try out some different framebuffers; both Kamarang and Iriri seem to resolve the problem.

However, now I can only use 2 out of my 3 monitors at any given time. If I unplug one monitor, the one that was previously not working starts working, I then plug in the monitor I just unplugged and it is not recognized by the OS. I currently use 3xDP connections, but it is the same result with 2xDP and 1xHDMI.

I have tried the Black Screen Patch (board-id) which made no difference. I then downloaded IORegistryExplorer and searched for "display" and found only 2 outputs listed under Kamarang. All 3 monitors work fine if I do not define a framebuffer and select InjectATI (but am plagued by random hard locks). Any ideas? Thanks!

Hardware:

• i7-6700k
• msi z170a sli (latest bios)
• sapphire vega-56
• 32gb ddr4
• toshiba 1tb nvme ssd
• 1x dell 27" ultrasharp (display port)
• 2x dell 24" ultrasharp (display port)

Software:

• mojave 10.14.3 (followed the skylake guide here)
• my config.plist
• drivers64UEFI: AllocFix (fixes random issues on startup with msi motherboards), ApfsDriverLoader-64, AptioMemoryFix-64, EmuVariableUefi-64, HFSPlus
• kexts: AppleALC (1.3.6), IntelMausiEthernet (2.5.0d0), Lilu (1.3.4), SMCBattermanager (1.0), SMCLightSensor (1.0), SMCProcessor (1.0.2), SMCSuperIO (1.0.2), USBInjectAll (0.7.1), VirtualSMC (1.0.2), WhateverGreen (1.2.7), XHCI-unsupported (0.9.2)