itch.io

Dude, I'd be THRILLED if you put me in the credits, I'd show it off to everyone I know if that ends up happening! I'm so glad you enjoyed my ideas and I can't wait to see how you interpret them into the game! While I was thinking of how to respond, I realized something that might be helpful to you and had a few final ideas for you to do with what you please!

If you're having trouble thinking of new designs to make new dolls with, since I notice you make all of your dolls really unique, you could do things like the top half of a clown doll where the legs are replaced with one of those rainbow-circus-balancing balls, a bug-looking doll that looks similar to Uniqua from the Backyardigans or one of those Quami from Miraculous Ladybug (sort of mono colored or spotted body with big eyes and those little curly antennae on top), an action figure (could even be a vintage 90s action figure not removed from the original packaging), or maybe one that's just a stuffed dog. Hell, thinking about what YOU could make out of a hostile Jack-in-the-box makes my blood curl and I'm all for it! You could also sort of take some basic models and dress them up as nurses, cow-girls, tuxedoes, clown outfits, different skin textures/designs. Idk, I thought that might help a little if you were short on designs recently xP

Now, here's a specific idea I thought you might like, a little doll body that has a CRT TV for a head! My initial thought for this one is that it could be a kind of doll that a company made so it would work with an AI program they're selling to kids, but if that doesn't work with the time frame of the story, then it could just be for playing VHS tapes, DVDs, or just be a fake TV for the sake of making a doll with a TV head. Whatever the case, when you start testing this doll one of the tests will cause a static sound to start playing. In a similar vein to how removing the Kate doll reset the surroundings, triggering this doll's test will spawn in a bunch of CRT TVs around the facility, all of them displaying a creepy moving image (I'm picturing a screen full of eyes looking in multiple directions). The TVs could be on the floor, on the shelves, in corners, where ever, the main goal is that you would have to run around and deactivate (or smash) all of the TVs before the time runs out (bonus points if something like hands or a giant head are slowly coming out of the TVs or the walls around the facility).
This next part is a stretch but you could make this even worse if a second test triggers another event, where there are so many TVs that they've stacked on top of each other to form a MAZE in the big rooms of the facility, but only a couple of them are actually on (maybe even only the ones that showed up in the first event are on, and you have to navigate the maze in order to get to them)! That part's a bit of a stretch, but it's your call whether to use any idea I give you :D!

One thing that I noticed that I MASSIVELY respect about you is that you don't animate a THING unless you really need to (something that I need to pick up for my own projects :P) and tend to let the physics system do the moving for you, so I get that this other idea might not get used. I was thinking about how cool it would be if there was a doll that for EVERY test, you would hear an inhuman humming or wailing coming from somewhere in the building. This is because a monster would spawn into the facility, and trying to touch the doll in any way before dealing with it would have you hear rapid footsteps before it kills you. Going out to find it, you would encounter a giant pitch black figure with no arms, standing face first into a corner. The procedure tells you to slowly approach it, but to freeze when it stops making noise. A split second after it stops making it's noise, it's head will snap to face you without the rest of the body moving, 180 degrees if it has to. 4 out of 5 times, it will stare at you until it decides to leave, in which the lights snap off and it vanishes the moment it happens. The odd one out though, it will scream and begin stomping towards you, moving at a speed slightly faster than the player. You have to run to the testing chamber and close the metal safety door from the inside before it catches you, and once it's stuck on the other side it'll scream again before the lights flick off and it vanishes. 
Now that I think about it, you might have made it so that Susie is the only one who responds to every test, so feel free to have the monster pop up to as many or as little tests as you like!

Finally (and this is the last idea for this game that I'll ever bother you with), I wanted to say something about the "Containment Mode" I suggested in the comment before. I completely get why you wouldn't want to do it, it's quite a bit of work, is basically a separate game and doesn't seem like it fits the story, but I wanted to finalize the idea. This is mainly so I can get it out of my head, but I'd be happy if you had it in case you ever decide to revisit and expand the game (possibly for a $5 Steam release? 0_0 I'd certainly buy it and I KNOW they love scary doll games over there). That being said, I understand if you skip this section if you've decided that you don't even need to consider it.
The main reason I like the thought of this mode so much is because all of your dolls work so well as their own unique puzzles, that it would be a lot of fun to have to juggle several of them at once, like a kind of Mania Mode! To start it off, the job would have you entering a different section of the facility with four rooms connected in a circle; the first has an open pipe on the ceiling, the second has a small cage in it that's too dark to see into, the third has the incinerator and a chair, and the fourth has a breaker box with a power switch. In my concept here, the character you play as will default to holding a camera when they're not holding anything else, that can light up an area in front of you with a brief flash before needing a short recharge time. Before the night starts, you're briefed on the job you're supposed to do, which is to incinerate the dolls that were marked as possessed with the incinerator, but the anti-flammable material that so many dolls have been made out of has damaged the incinerator over time, so the incinerator needs time to reheat itself after every use (indicated by a red light above the incinerator that turns green when ready). As for the thing in the cage, they're not entirely sure that it's possessed yet, but one other employee has not been found since working in that part of the building, and it is possible that this happened because they were the only person so far to stay for more than 10 minutes in the presence of the cage (this effectively works as your timer, your reason to race to complete your job as fast as possible. For maximum terror, edit the maximum amount of time to be about 40 to 15 seconds above what an optimal run would require. I believe the best way to do it is to start with 40 to 15 seconds, then add 1 minute and 30 seconds for every doll, you'll see why in a second). On the bright side, if you go missing, they'll know for sure that the doll in the cage is haunted!
In my concept of how it would play, I broke the job up into separate nights so you would only have to deal with specific bunches of dolls rather than all of them together, but I could see it being one long night if you like that better for story purposes (maybe consider doing that as a hard mode, or rename the stages into hours instead of nights :P), where before each night officially begins you can go into one of the four rooms where you can see all of the descriptions for every doll you'll face in that stage above a table so you can remind yourself of what they do. To start, you'd activate the incinerator, the thing in the cage would have it's eyes start glowing red, and the timer would officially start. In my head, the incinerator takes 1 minute and 30 seconds to warm up, the first doll drops the second the night officially starts, and the dolls keep dropping every minute without your say so, which will quickly make this into a game where you prioritize eliminating the most problematic dolls first.
Before I get to what some of the dolls could do, I want to address your concern that this mode wouldn't really fit with the story, because I think of it like this: Every doll that ends up down here will be thinking similar forms of this statement, "Why the hell do they want to destroy me?! I didn't do anything wrong, I only followed what my instincts told me to do! It was everyone else's fault for triggering my instincts and being where they were when I reacted! And who the hell do YOU think you are to damn me for my actions?!" 
I think it works because their rage, denial and grief is a reflection of the main character's and they're fighting just as hard as he is to see the other side of this nightmare. Effectively this traps him in a sort of mental purgatory where he's forced to burn spirit after spirit, each of which clings to the same argument that he did since all of this started.
Now onto what I think the dolls would do (I'm so sorry, I just finished the whole reply and had to come back to warn you that I put EVERY doll currently in the game in this next part. Feel free to skip if it's too long)! Because they're now angry and desperate, several of the dolls have become more aggressive with their powers. Ones with kinder personalities and weaker powers like Abby and Karen won't really do anything yet still work as threats because you need to burn ALL OF THEM before the time limit is up to beat the stage; while ones like Anna and Victoria could frequently shut off the power which pauses the incinerator recharge (or accelerates the cage doll's timer, same thing! Also, Victoria's power outages would feature a 15-10 second time limit to get the power back on)! In order to deal with dolls like Anna, I came up with this idea called "The Time-out Chair". It's a chair that you can put a doll in which will pause their power for 30 seconds before they fall out of the chair and become a problem again, but just holding some of them like Andy is enough to keep them in check. It could even work so that you could sit in the chair to pause the timer, although that might not work in a final product. Clawdia could activate any time you have to flash your camera, flinging herself at you hard enough that if she hits you three times, you die. Maria could hide herself somewhere in one of the rooms to make burning her more of a problem, but Andy who has a similar power with a more aggressive personality could occasionally try to shut off the power! Abby would just make you feel bad :( but Tina is a whole different beast, because if you accidentally get her in your camera flash, she'll have a PTSD attack, scream and race forwards to kill you! When Tracy spawns, a cabinet between you and the incinerator will slam from one wall to the other, making an obstacle that you have to run past with the right timing. Bella could make you waste time with her depression hallucinations. Olga would work much the same as before, but she needs a sound que or something so you know when she's started hunting. While you're dealing with all this, suddenly a voice starts counting down before she's even hit the floor from the pipe, "5... 4... 3..." LILY. Get yourself or her to the chair before she can finish. BunBun could be really unique, in that every 2 minutes he will spawn another BunBun, and if left alone for another 2 minutes, BOTH BunBuns will each spawn another BunBun, at which point you're probably just screwed tbh. Erid's power could evolve so that she would start spazzing out even if you aren't holding her, meaning you would need to put her in the chair to reset her before she can give you a seizure even while you aren't touching her (or you could add a pair of scissors, but idk what else you would use them for other than this)! Finally, Kate would work in a similar way to Erid, forcing you to have to put her in the chair to stop the building from collapsing.
THANK GOD that idea's over it took forever to write and reread it! ;-; I'm glad you got all the way here if you did, thanks for suffering through that with me! ;D Yeah reading it for myself I can see that's a WHOLE SEPARATE GAME, but I really enjoyed the idea and I'm just glad to get it out of me! Oh, and no, I don't really know what dolls would be grouped together for what nights/stages, that's the one part I never managed to figure out, I just know that them being dropped in a random order sounds WAY more fun than in a linear order. :p

Thank you so much for reading all of this if you indeed did, and I don't mind if you don't use any of it, you have a lot on your plate right now I bet! xD Please do let me know if I can help you in any other way, I gotta earn my keep if I'm ending up in the credits! :)