I can't really comment on the primary issue in this bug anymore, as, since I have to enter ATA passwords into the BIOS at boot time, I got tired of trying to do it blind, and moved my primary display back to being plugged directly into the HDMI 2 port on the NUC, and left just my Oculus Rift connected to the GTX 980 in my Razer Core.
But, I figured I'd set mine as suggested, as it shouldn't hurt anything, right? So I went into my BIOS and unchecked "Ignore Thunderbolt Option ROM", checked "Thunderbolt Boot", and also checked "Thunderbolt USB Boot" while I was in there, in the hopes that might enable a keyboard plugged into my Razer Core to be initialized in time to use it to type in my ATA passwords to the BIOS on boot (it's normally not, which makes any Thunderbolt dock almost useless to me).
Yeah, so I did that, reboot, and got no signal on my primary display, plugged in directly to the NUC or via the Core.
Through trial and error I was able to determine that checking "Thunderbolt Boot" was the culprit.
I also noticed that, with "Thunderbolt Boot" checked, my keyboard plugged directly into the NUC via a USB hub didn't even light up anymore either while the Core was connected.
Unplugging the Thunderbolt cable to the Core restored signal to my primary display, and I was able to uncheck "Thunderbolt Boot". I left "Thunderbolt USB Boot" checked and "Ignore Thunderbolt Option ROM" unchecked, but haven't yet tested to see if that does anything useful for me because it's now 2 in the morning and I hate computers and I'm going to bed ;-)