I am working on a particular section of a building, and I'd like to have NPCs that are not themselves invisible, but hidden from the compass (no "radar blips"). Is there an option to do this that I am simply not seeing? Or is it something I need to make a custom script for?

I would disable them and when the player reaches the section where they should be seen on the radar enable them with an activator.

Or give them the steathboy effect and script an activator to remove the effect.