For this game to unlock more scenes with the ghost you need to upgrade the detect ghost/ holy power skills.
To do so you need to use Holy Orbs at shrines.
The gray shrines increase these skills while gold shrines give you new staffs/abilities/items

You want to first get all gray shrines to unlock all scenes that give you more holy orbs
then once you do all the Requests/ environmental ghosts go for the gold.

The rescue missions are time based, and the longer the time the more raped the person you need to rescue will be.
The copper statue in the middle of the cities can usually give/take time for these missions so unlock these lasts to get all the scenes.