It's a long shot, but asking never hurts I suppose.
I wasn't able to get the achievement for all optional Molly scenes in Book 2. I tried to figure out what I missed with the walkthrough but I've no idea. If anyone has any tip/advice that would me prevent to replay everything, thanks. I think there is nothing left to do in my game after clearing last act, so it was probably something skippable. For what's worth, the only "peculiar" thing I noticed is that the wrap gift dress didn't trigger any sex scene when I got and present it to her (only a scene with no sex option), but maybe that was intended.
there is a lot of content for Molly,
- Make sure you'll have the Kings Dragon fully upgraded.
- Get Akane new outfit for elsewhere, (Visit the dojo at night)
- buy the gift wrap outfit for molly (use computer)
- the dancing scene
- the chair dancing scene
- the hot spring (visit once then talk to Emily)
- then there are the private secretary scenes
- the repeatable once when you talk to molly in the pub late at night
I don't know the exect trigger for them thou, nor if this list is all the content
