Sister Eunice is a character in American Horror Story. She is often involved in the dark and twisted storylines within the series, typically representing some form of religious or institutional authority with her own secrets and malevolent tendencies.
One memorable moment could be when she reveals her true, more sinister nature. It gives a shock to the viewers as it subverts the initial perception of her as a typical religious figure.
I'm not sure specifically which 'Mary Linda' you are referring to in 'American Horror Story' as there could be many characters. Maybe she is a minor character or a new addition in a particular season that I'm not familiar with.
Since there's no clear information given about either Mary Linda or Portee in relation to 'American Horror Story', it's hard to say if they are related. They could be two separate entities with no connection at all, or they could be part of a sub - plot that has not been fully explored yet.
The 'American Mary' is a horror - themed story. It's about a medical student named Mary who gets involved in some really dark and unethical practices in the medical underworld. She starts to perform extreme body modification surgeries and gets caught up in a web of dangerous and immoral people.
The central character is Mary. She's the one whose actions drive the story forward. Then there are her clients in the body modification business. They're often depicted as having unique and sometimes disturbing personalities. But overall, Mary is the main focus, and her relationships with these other characters in the seedy underworld of body modification form the core of the story.