Guard / Civilian Patrols

You can make NPCs walk around the level in stealth mode using SpecialObjective and SpecialObjectiveGroup Elements. Per NPC, you place several SO Elements. They act as check points the AI moves between.
A basic setup for your SOs is the following:
Enable Repeatable, and Use Instigator. Set AI Group to whatever type of AI uses the patrol. Path Style destination and Path Haste walk. Also make sure to add the AI type to the Access Flags. Further down you can also set Action Duration Min and Action Duration Max to tweak how long the AI remains at this SO.

To easily randomize between the SO checkpoints, spawn a SpecialObjectiveGroup Element and add all SOs of your patrol to the followup Elements list. Set the mode to randomizer, enable Use Instigator and set the base chance to 1. Make sure each SO of the patrol has the SO Group Element in the Followup List as well.

Now all you have to do is place an EnemyDummyTrigger Element, link it to your enemy or civilian, set it to spawn and make it execute the Special Objective Group.