What are the quick and easy requirements for Fiona's True ending? I interacted with her as little as possible in my first run because I disliked playing the victim, so not sure if I got it or not and apparently need it for the new content.
You have to finish it entirely -- you'll know when it happens (a dramatic UI change happens, after the green door event). Then go through a day and start New Game Plus (the option to clean up in Fiona's room in her endgame). You can then start it in the afternoon in the greenhouse in your new game+.
And yes you have to be the victim throughout the entire arc that's required. No revenge without a thing to get revenge over!
.....or just download this "dummy save" that lets you access the new content with basically no friction -- you have a lot of money and your skills needed for the new content are already maxed out: https://mega.nz/file/vc8QyADb#s-zlbYJjjB7gu9K2vfLxfhe6Pkt1r1PZjCyXY10QLos
(Click Load, not Import, for this)