A few years late to the party, but I just powered through this game over the past few days. It was a masterpiece, of course, but for clarity's sake I'd like to post the following nuances concerning the endings...
End A - Yes Defeat Cinderella with 0 sins and with all 8 heroines as companions (excluding Leaf and Red Hood, who would otherwise be "9th" and "10th" ... so, Dorothy, Elma, Victoria, Goose, Elisabeth, Catherine, Jeanne, and Miranda) -- but you must then touch the fog "by yourself".
End B - Defeat Cinderella under any other condition (more than 0 sins, or not having all 8 heroine companions). Touching the fog with any companion is also very much similar to Ending B. These endings aren't "labeled" but are a continuation of the otherwise very bland B.
End C - Complete the library collection arc. And I mean COMPLETE it... then follow the narrative.
End D - Complete the requests of Baphomet, and check the dungeon upon your return. (You may not think that's a necessary instruction, but I stopped short...)