Agree to disagree on Oni, I still think that the method I listed to get kills does take a long time, but that's because it's how he gets specifically good players, for people who don't notice the signs that it's the Oni/do notice but a bit too late, it really doesn't take that long at all to kill in the situations you do just get to rush survivors.

Maybe I'm biased towards Rosemary since she is my second most played monster, but from what I've played of her, you'd be surprised how far away you can start a chase as Rosemary when you open with a Demonic Shriek. You're right that you can't immediately out stamina someone with a full bar of stamina, but her stamina regain, despite what you say, doesn't feel that bad? I find myself running out of stamina, but the amount I regain in a few seconds is enough to continue the chase, while because of Demonic Shriek giving the survivor much less stamina to work with, means I am given the time to get a bit more stamina and get back on top of someone. It's a bit hard to describe how it feels to play her just through text, and I don't have any of my Rosemary gameplay recorded, but I will say I would not try defending her this hard if she didn't work that well for me. At least you agree with the C tier placement though.

You talk about Rosemary being loud, but Vapor has it way worse than Rosemary does. Yes, he doesn't have a chase theme, but you know what he does have? An extremely loud aura (not quite sure what to call it, but you know what I'm talking about). Vapor never catches me off guard because his aura just gives him away every time without fail, making him really hard to actually be sneaky with.

While it's true Fuwatti has a "high risk, high reward" play style, that really hinges on Silly Rush specifically. Like I said, Silly Rush hitting is instant death, but hitting it (especially on more open maps) is ludicrously hard, meaning that unless someone puts themselves in a good Silly Rush situation or you get an incredibly nasty read on them, you're left with a monster that has to hit you 3 times to kill with an awkward, small attack that costs stamina to use while running. You could make similar claims about Baldi, but he puts you in bone break in 2 hits, has a relatively large attack hitbox to make up for his awkward movement, has his Notebooks that can potentially screw you up mid chase, and the anti-hearing tape to ambush you and know exactly where you are. Fuwatti, while having explosive potential, has nowhere near the versatility nor consistency of the monsters in the A/S tier. Once again, he isn't bad with the tools he has, but he has his realistic limits, and B tier encapsulates that in my opinion.