This is as far as I got before I got stuck! This game is amazing and definitely a brain teaser! Great work overall!
Thank you so much for playing and thank you for the kind words! :D
and ooo you are very very close! This one may be a bit of my fault: since the clues aren't very explicit, the interpretation you have is understandable as well.
You could review the letter that starts with "To my dear s daughter" and some of the related cassette tapes.
[SPOILERS]
Its meant to be that one side of the family was more accepting of Mary and Angela's relationship. And Angela has more going on, but unfortunately you only get glimpses of it in that letter. This is because as I was writing clues, I wrote a clue related to Angela that turned out to be useless for the puzzle, so I took it out of the game but was unable to rewrite a new one before the game jam ended.