No, go crazy! You guys are being so nice and so cautious. You can be a little bit more assuming with the NPCs. If you think something is in their nature, feel free to use them a little bit, write a few lines of dialogue for them, etc. The main place where I care about making decisions on the success or failure of certain actions are anytime it might have a big impact on the story. Combat, extraordinary physical things, etc. Develop your own side plots and feelings, etc. If Sebastian has murderous dreams involving Ivy and Lily, spill them! I thought it was awesome!