Someone in the writers' room has a psych 101 textbook. I don't mind, but lots of the behavior is actually textbook. People don't generally make to do lists with "manipulate people I love" and "emotionaly abuse them" on them. Unhealthy people engage in behaviors to try to make other people react a certain way. Norma loves Norman and wants him to stay with her in her version of a perfect family. So she has made him dependant and covered up his mental illness and murders, so she can keep her do-over son and be happy. Its working for now.
Norman has learned to manipulate from the best. His conversation with Emma that leads her to homeschool is perfect. And it's not evil, he just wants to learn at home and spend time with his only friend. Emma being cut off from more people isn't a conscious goal of his, but it is a result.
Caleb thinking that forcing sex with his 13 year old sister wasn't rape is perfectly consistent with him raping her. There are convicted rapists who don't believe they did anything wrong because they didn't attack a stranger in an alley. I actually hope the show doesn't walk back Norma's story. It would be gross, and having a victim of sexual trauma, have moved on somewhat, but still have messed up boundaries, is much more interesting.