iGPU on my motherboard only has HDMI or DVI outputs, so I used an HDMI cable to my monitor for the test. I cloned my config.plist and made your modifications, and also changed to iGPU enabled as default in BIOS. But afterwards, about 2/3 the way through booting-up, the white Apple logo switches to having a red rectangle around it and the white progress bar turns green. After that the display freezes... but I think the OS actually continues to boot "behind" the frozen display. (I have a little mp3 tune play automatically as a startup item, and the tune does eventually play even though I can't see the desktop on my monitor). No idea why I don't have the luck you did with the config.plist settings, maybe it's a mobo difference from yours, or the fact I'm using HDMI, or the fact I recently started using lilu and WhateverGreen (whose guide, posted here on tonymac86, specifically says not to have any "Inject" boxes checked under the Graphics section in conflig.plist.)