There´s no guide right now, i can only tell what i did by now.
First you need to awake her using a filled princess urn in their altar; don´t touch her!. Gain 10 regin affinity, and break the seal to visit her by night. Theres a room(north passage) where you can wait to night and break the barrier from inside, defeat 4 invisible ghosts (founded by sound, more loud are they, more close are you). After defeat the four, go to garden an press the handle. Now the barrier is gone, and you can visit ghost princess in night! Next progress in her conversations, and reaching 3 hearts (his nightmare chages and with image from the knight) you are ready to next step.
After pick the princess´ ashes you need to recruit her, so, impreg her by using the Shorty Special (needed) and wait to give birth, next visit her again by day, and ask to be with you.
Next, camp and get the first hint to do:
1- Go to the Upper Church
2- Find Mary-Annette (She´s on Grim Forest)
3- Search more in her house!
4- Get Catalyst Dagger, Prayer: Life Breath, Nya-Nya Doll and Death Not for the ritual (im stucked here).
Theres all i can tell.
Edit: Oh, one more thing, rise her love stat to begin the search. If not, you maybe stuck.
