Seriously, thanks, I feel like such an ***** now. I've rooted so many devices in the past, even with unofficial CM ROMS and had success, and I've never seen "allow OEM unlock" as a dev option.
This is the readout from my PowerShell when I try to flash the TWRP into my phone. The phone is recognized by windows, and shows as authorized under adb devices
When attempting to use the code to unlock my boot loader, I get this: