Spoilers! 100% Guide

[Enthu]

I highly recommend just choosing whatever you want for your first playthrough. And this may not be perfect, But I just got 100% and I'm pretty sure I remember all the important decisions. The game only really has 2 paths, but its not very obvious. Here goes, sorry if explanation sucks.

First off, The story is not really dictated by which Queen you choose, nor if you choose to be king. The real switch for which scenes unlock during your playthrough, is which supernatural character you side with. Either the Sun Goddess, Or the Witch. Also any dialogue choice that doesn't say it affects the story, does not need to be selected differently for 100% achievement and all scenes/cards. So if you don't want to read anything different and keep the skip feature working, just choose the same one every time.

The most important decision is actually where you give the magic stones. Giving them to the Sun Goddess puts you on a path where the characters who worship the sun religion play a different role in the story, this will dictate which scenes you get as you go to the remaining lands. So, do one playthrough where you give the magic stones to the Sun girl, then another where you give them to the witch.

One other important scene is right after you find out Jeanne is trying to take over, and Paretta has been arrested, you need to go to the wall from the courtyard in the main kingdom. There you'll see her locked up in a cell, you need to free her to see a couple bonus scenes, I did this while siding with the witch, but I think you can do this on either of the supernatural character paths. Freeing her is what gives you the option to escape from prison instead of Jacaria Freeing you herself. In the tunnel you escape through you unlock 2 scenes, you could otherwise miss.

Beyond that the optional scenes at the end are just whether you choose yourself or the co-responding queen. Witch = Jacaria, Sun God = Liliana. But on either path you can choose yourself.

TLDR;
I believe you can hit every scene with 1 save in the 2nd sun goddess scene, where you either give her the stones, or keep them to give to the witch.
Then one more save at the end just before choosing yourself or your corresponding queen (Witch = Jacaria, Sun God = Liliana).
Finally, you'll also want to save right before you choose your girl at the brothel. This doesn't change the story at all, so you can just save right before it, do one, reload, repeat for all 3.
Also Don't forget to free Paretta on one of your files. Doing so unlocks the dragon scene and the solo Remy scene.

Pretty sure that's 100%, if this isn't enough info, let me know :)