I have 2 questions. Question 1 What does affection do in the game?
2 Who can you corrupt in Story Mode?
1) Nothing much these days, is my impression. The affection and corruption stats used to have a bigger impact but have largely been supplanted by the serum system.
2) For now the Mum and Sis at home and at work Tasha, John, Penny, Diana, and Ms. Dee. The last-named can only be dosed at specific story points, the others throughout the game. Lauren and Julia can't be got at through the regular serums, but are tied to specific (unmissable) storyline events.
... oh and the new character, Kagney, but I haven't played through her content yet.