(Almost all of the following will apply to the previous FNAF NPC addons in a future update)

Each animatronic now follows its own specific A.I. Level, rather then a predefined speed/damage system. The A.I. Levels are limited from 0 - 20.
0 Being inactive, and 20, being extremely active.
A.I. Levels affect the animatronic speed, search / lose radius, and damage.
(Each animatronic has their own separate command for A.I. Levels, resulting in varying speeds between them)
The A.I. Levels can be changed in the "A.I. Levels" tab, under "FNAF" -> "FNAF 4 NPCs" on the right of the spawnmenu via sliders, as demonstrated below.
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=524643582&fileuploadsuccess=1

• Default (Same A.I. Levels as Night 5)
  
• Night 1
  
• Night 2
  
• Night 3
  
• Night 4
  
• Night 5
  
• Night 6
  
• Custom Night
  
• 20/20/20/20
  
• 1987

The values for these presets were ripped directly from Five Nights at Freddy's 1, so they may not be accurate to Five Nights at Freddy's 4.
With presets, come custom presets, meaning you can create your own "Nights". (Please keep in mind, the maximum A.I. Level is 20)

Thanks to the newly added A.I. Levels feature, attacking works a bit different.

• If the animatronic has an A.I. Level of 1 - 10, the victim will take damage during the first attack, and will be jumpscared during the second attack, resulting in death.
  
• If the animatronic has an A.I. Level of 11 - 20, the victim will be jumpscared the first time they are hit.

The higher the A.I. Level, the faster the animatronics will run.
If the A.I. Level is 0, the animatronic will stand still.
Each time the A.I Level goes up by 1, the NPC gets a bit faster, and will have a bigger search / lose radius. (This may have a negative effect if you want a slow-moving animatronic to chase you in an extremely large maze, so there is a command to toggle this feature)
Finally, animatronics play their idle animation when they are stopped now, instead of continuously running in one spot.

Originally, the animatronics would play a sound ripped from FNAF 4 every 15 seconds once spawned. This has been changed, so the sounds will now play within a random time between 15 - 30 seconds.

In the previous FNAF NPC addons, shooting the Runner Animatronics produced a blood particle, as if they were human.
Although this seems to fit for Springtrap (and possibly the FNAF 1 Animatronics), the Nightmare Animatronics now emit sparks when they are shot at.

When an animatronic is killed, their death ragdoll will maintain their original pose then fall.
(This won't be true for the FNAF 1 / 2 NPCs, I'm not sure about Springtrap)

The collision of the animatronics has also been revamped too.
In the previous FNAF NPC addons, spawning multiple of the same Running Animatronic would cause them all to merge inside eachother while running towards the victim. Now the Runner Animatronics group together in almost like a wall form, instead of merging.
Players can now collide with the animatronics, though I am not sure if this will be so in the release.

-Custom Night
-Improved A.I.