Since October has concluded, here is my list of least scared to most easily scared EN, updated as of Ame's Mortuary Assistant playthrough to confirm my thoughts on her
TIER 1:The unfazed
>Ame
Literally unfazed, too autistic to feel fear and has to pretend to be sarcastically scared at moments to show that it might be affecting her.
Often follows jump scares with a delayed "Ohhh did you guys see that? so scawy"
>Mumei
Same as Ame, too autistic to feel fear and no sells everything, hasn't played a super scary game yet though but I'm positive she could no sell it too
TIER 2: Feel fear sometimes but can handle it without much problem
>Mori
Screams in reaction to some jump scares, "oh fuck oh fuck oh fuck" when she is getting chased.
Perfectly fine otherwise and does not hyperventilate
>Ina
Cheap jump scares can sometimes get her, can go through games fine honestly speaking
TIER 3: Need some breathers here and there, scaredy cats in general while playing
>IRyS
Jumpscares get her but she recollects herself pretty quickly, her and Gura are the same in how they receive horror games
>Gura
Screams a lot in response to jump scares, can panic when getting chased
She has completed many horror games though and can handle it better than any below this point
>Fauna
Takes breathers in between to collect herself if too scared, has a heartbeat above 100 all the time when playing horror and also likes having support if possible
TIER 4: Extreme scaredy cats who have sharp reactions to horror
>Kiara
Doesn't even need horror, frequently gets jump scared in non-horror games.
She is absolutely terrified when playing a horror game and will prefer to bring along support otherwise she won't play
>Kronii
Loses her shit and starts hyperventilating in real time, feels scared even in groups of 4
There will be a stark difference between how scared she is compared to her collab partners usually.
Tier 5: Has the reactions of a trauma/PTSD victim to horror, most easily scared Hololive member in general
>Bae
Always needs to recollect herself before taking single steps in horror games, if something scary happens she will literally shut down and lose body function, especially if she's playing.
Can feel lots of fear and hyperventilates while just watching someone else play
I'm pretty sure I got all this right and Ame is the bravest overall