The major soft locks in the game that I know but are easy to miss are
-Victoria. ergo not having the book when she confronts you with 8 slaves.
-Camilla. Ergo not playing through sarah's doll story while she is free and then enslaving her during the second date after triggering the event with Camilla in the city
-Brittany. not having normal Julia before talking to her
-Not triggering the bimbo Mrs.Rack class to get Hilent
- also when getting the monster ranch through the ice queen story if you don't have erin and eric in their normal forms it breaks the game
The whole point of the game is the soft locks. I personally kinda think it was a bad choice to pair a multiple endings game with a classic grind jrpg. But if you fail then you just have to think and try again. I wanted to write a guide like that 3 months back. I was kinda waiting for Hilent bedroom scenes b4 I did and now changer is working on finishing his other game so back to waiting. :P