Hey, Zak here!
Regarding unlocking images and other content:
We currently have a few tips on Patreon about how to unlock certain harder scenes, but we don't have an official guide yet.
I completely understand what you're saying tho. with so many variables, it becomes difficult to keep track of everything you've done or discovered. Actually, this is something we want to address to make things simpler and more accessible. We're planning to implement memory logs that will not only store the images for you to review but also keep a record of key decisions you've made and knowledge you've gained about the characters. I think this will help you see what you might want to try differently.
However, even though we don't have guides or the logs available yet, I'd be happy to help if you're looking for specific images for particular characters. I can also check if there might be a bug on our end that's listing more images than there should be.