Just wanted to follow up to let everyone know that I have fixed the "Custom binary blocked by Reactivation Lock" error that had bricked my device.
I downloaded the recovery file (I'll update with a link to this file)
I flashed with Odin 3.0.7 (PDA)
It FAILED. (I expected this)
I unplugged USB, pulled the battery out
I put it back in, booted into stock recovery with Power + vol down.
Selected Normal Boot
Went to settings and turned off RL. LOL
Restarted Phone with normal Power Off menu - still fine
After reboot, opened SuperSU, still showed QuickBoot with root access
Opened QuickBoot, tapped on Recovery
It booted into TWRP (I'm on 18.104.22.168) - no problems
Rebooted again. No more error when booting to custom recovery
** the battery pull trick after Odin flash fail I picked up from the Note 3 forums **
** If you have SECURE FAIL: KERNEL, you may need to perform a factory reset during the first boot after battery pull! **
A big thanks to all those who helped me via the forums and PM!