Several women are as objectified as you can get, I'd say, by a small number of people. Strictly speaking, I'm not sure if all of the objectifying going on is sexually motivated as such, but some of it definitely seems to be. In any case, it's an exceedingly atypical type of objectification.
Large-ish? Sebastian Stan is 16 years older than Daisy Edgar-Jones (their characters date and have sex), but I didn't think about their ages until I was told by my co-watcher at some point during the movie. I just perceived them both as young-ish adults, although he does look somewhat older than her.
No. However, a grown woman tells that she doesn't have much to do with her mother; there's obviously something wrong between them, but I don't remember what.
We don't know 100% for sure, but it definitely seems like someone who is at the very least aiding and abetting was a victim of the same crime done by the same person before the events of the movie.
Not sure. We do see a woman in front of a mirror holding her hands on either side of her face as if stretching the skin, like some people do when they find their facial skin insufficently tight. However, if that's what she's doing, it may not be because she herself doesn't like her appearance, but because she's afraid that her husband will soon find her too old-looking for him - which in her case might mean literal death.
Something akin to it, at least. The bad guy talks to his victim as if the horrifying thing he is and will be doing to her and others is completely normal. He stays calm and casual and keeps a light-hearted tone while she's screaming, struggling and crying.
Yes, but not for the purpose of inflicting pain or extracting information or for any other typical reason. The people who are tortured are actually given painkillers. That doesn't change the fact that it's torture, though - both physical and psychological/emotional.
We don't actually see a limb being sawn/cut/chopped off, but we do see some cutting into the skin before amputation, and we see lots of severed body parts.
No one in the movie is diagnosed or referred to as mentally ill. There's obviously something extremely wrong with the main antagonist, but we don't know what, and nothing is said about it. (He's probably a narcissist, possibly a sadist, and definitely high on the psychopathy scale. A secondary antagonist, who shows up late in the movie and is also violent, is likely also high on that scale.)
People kept in chains inside locked cells. The cells are rather large (and un-jail-like), but it may still be triggering for some. We also see someone inside a dumbwaiter (food elevator), but that's extremely brief; the person bursts out of there a split second after it opens.
BIG SPOILER!!! you hear a couple of gunshots in the movie. and
Steve gets shot in the head at the very end, and you see the bullet go into his forehead.