And lastly I'm still missing three scenes, so did I miss something or do you get them when you get further?
Top left: you need to complete the encounter with the spirit before you get the book (and unlock the gallery) without getting touched by the spirit as you destroy the crystals.
Third crystal, top row: It the North-west tower, on the second floor, put on the Maiden Suit, interact with the mirror.
Third crystal, second row: I don't know. I do not have it. I guess it has something to do with the slime quest. In the first area, in the zone before you leave the place, there is a vine on the wall. It goes to a hole hidden by a tree. I don't know how to do that quest.
Also, nothing happens when I try to interact with this mirror, am I forgetting to do something beforehand?
Wear the Maiden outfit, it is the one that allows mirror travel.
In the quest to find the needle it says that I need "Decayed time" to go through the portal by the statue which I don't know where to find, but it seems that other players managed to get the needle so, I'd like to ask how to get it.
Defeating a ghost enemy (one of the enemies of the area) provides one Decayed Time. You need one per travel through the special passages.
Note, when you reach the second statue, switch to a Suit with high defense and heal, you will need it for the boss in the next room. And have filled the SP gauge of all the suits so you gain their bonus (active or passive). One provides a healing spell, one provides a passive stat boost, another a passive regeneration, a third a passive doubling of money reward and the fourth passive gives a 15% maximum HP increase.
For the fight, use Purge and Paralyze to bring him down. Your reward for giving the Knitting Needle to the woman (seamstress?) in the village is the Cutie Suit (-150 HP, +25 Attack and +25 MP).
You have to pull the chains to unlock some secrets
To be more precise, the chains are to the right in the first room, near the dining table.