After Defeating the Caretaker, you'll get a key to enter the house, but Before you Do head to the rear of the garden and collect the hairbrush from the far left corner and enter the house from back door. Collect the sketchbook from the table and move upstairs to open the door to your left where the Boss: Wraith is waiting for you.
Do not underestimate this Wraith as he is different from other Wraiths and also more powerful. You need to keep it in the center of the room(away from walls) as the paintings on the wall helps the Wraith to Heal faster so try to make it quick. Use Specter Oil(if available) and Lay down a Yrden to keep the boss busy. Let him pin it in the corner near the door you entered through, this will also help to finish him quickly.
Searching and Placing the Items
Head to the bedchamber after you've successfully defeated the Boss Wraith. There from the end of the room collect the quest item and then examine the body. once your Down, head far left of the garden to examine the easel and then bury the remains. Now keep the hairbrush on the grave and summon the ghost to get back into the painting. Make sure of those spectators and clouds of ghost bees around the garden.
Note: You're unable to meditate once inside the painting.
Now you need to uncover the two "memories" outside: one in the south-east and second in the north-east corners. Use Witcher Sense to locate three items and do visit both of them. Once you've collected the items you need to place the items as given below.
South-east corner:
North-east corner:
A large specter will spawn if you have placed all the items correctly. You need to kill it and then head inside to examine the painting far end of the wall. Now Light the fire at the fireplace with the candle nearest the fireplace, take one in the middle. Another Specter will spawn and after taking him down will open the door. Go upstairs and return to the bedchamber. Place the towel from the floor on the washstand next to Olgierd and as the door opens go through. Pick up the bowl of fruit at the back of the room, goblet from the window and simply examine the painting. Place the collected items on the table next to Olgierd. It should be grapes, goblet, apple(Left to right).
Take Down all the specters and keep following the marker. As you reach, start collecting all the chalk and candles from the back of the room first and then examine the pentagram on the floor and place some candles surrounding it. As the Fire breaks out check the painting, it should have snow coming out of it.
Once You are outside, do not waste time admiring the scenery and to find an open cellar hatch just head right of the steps leading to the house. Use Witcher Sense to examine the area(door at the end) and collect all the items littered about the place, put the mug in Olgierd's hand, the marriage contract in Iris' father's hand and get ready to face off the spectres.
Head upstairs and Use Witcher Sense to examine the room and start collecting the items and place the large bowl in front of the dog, the small bowl in front of the cat, and the food tray in the caretaker's hands. Now get to the marker and read the letter on the table, and then prepare to face the next Boss Fight: Iris' Greatest Fear.