So, somehow this slipped by my radar, but this guide is now largely obsolete! Pretty much everything done here now seems to be automatically handled by FOG after the transition to iPXE 2.0. FOG will now generate it’s own signing keys and seemingly sign the kernels for you, and provides a dedicated boot menu entry to enroll keys via MOK! I’ve yet to test this myself so happy to be corrected if I’m missing anything here.
Additionally, it looks like you can pretty easily migrate existing keys into this setup with some install parameters. I’ll be updating my ansible role to acomodate these changes soon!