Alright, I took a look. My suggestion is to drag those NPCs from the Compendium into the game, then turn off the Starter Set from the compendium settings for your game. That will remove the Starter Set NPCs from your player's view, while leaving them accessible to you. It won't remove the BRCore NPCs though, I don't have a solution for that. My suggestion is to ask your players not to look. As a last resort, you can turn off Compendium sharing, then you can have access to everything but the downside is your players will have access to nothing.