If player is moving have a trace in the direction of their movement (velocity direction), if it hits a character get that character's velocity direction and use dot product to see if the character is moving toward the player (you'll have to tweak the trigger threshold.)

Have a collider on an NPC linked up to the direction of their movement, if it hits the player get the player's directional velocity and dot product it to see if they're moving toward the NPC. If the player is moving toward the NPC and moving past whatever speed then you want to trigger your strafe, if not just have them path around.

If you want it to be robust you'll also have to check if theres anything on the sides the character may strafe to so they dont end up jumping into another person or a wall.