I tried 20/20/20/20 for FNaF 1 from play store and they don't move 100% of the time, maybe around 80%

Not sure. Could possibly be because it is hosted via pygame, but for other sources aswell, it should be listed as 20.

I was experimenting when I recreated the game in pygame and kept trying to change the maximum number generated and 30 was the only one that was closest to all 20 (btw this was in FNaF 1)

Source?

I'm sure the number generated is from 1-30

that applies best to fnaf 1 and 2, but it's far from the reality in UCN

the movement opportunitys are not that regular here.
example- nightmare have an opportunity every 5 seconds. Ballora and Toy chica every 14 seconds. toy bonnie every 15. PhoneGuy every 20
a lot of them are not time related, some have a movement opportunity everytime you open the cameras, like BB and JJ ( yes, the nightmare's movement opportunity, per example, just work when the cams are up, but it's every 5 seconds the same. BB and JJ will always have an opportunity when u open the cams)
some of them are not RNG related, like the main marionette phase, it doesn't work with oportunitys

the numbers generated for movement oportunitys are not from 0 to 20 in this
if they were, a 20 AI ballora will appear every 14 seconds 100% of the time, and she doesn't, she appears about 50% of the times she can appear