Mav looks about the room, tips his hat to the invisible giggling lubberwort and moves back out of the room and heads to M8

As they leave and shut the door, Barbär gathers whatever loose dirt or pebbles or any kind of debris in front of the gap just under the door.

If the debris is moved if or when we come back, we will know it had left, or at least opened the door

(Reminder: Detect Evil and Good pings on aberration, celestial, elemental, fey, fiend, or undead)
Your detect evil and good is not detecting any of those things. The giggling continues.

M8 - DINING ROOM

Large windows form the entirety of one wall, looking out on three planted beds filled with vegetation. Within this room, a crystal chandelier hangs above a table made of dark wood. Six matching wooden chairs with scarlet cushions surround the table. A seventh chair sits alone in the far corner. In addition to the furnishings described above, this room is adorned with unremarkable tapestries that depict grapevines and the process of making wine. The buffet contains silverware and a service for six.

"Service for 6, yet 7 chairs....hardly appropriate etiquette.  My thoughts on this Fistandia are dropping by the moments...." and Mav scoops up the silver in to a pouch.

[Sleight of hand: 23]

"That is odd... I can see 6 or 8 but why 7?"  Isa cautiously enters "Any of those special books in here?"

Investigation:15 

No books in this room.

With a shrug, Orvok backs out of the room, and lets Barbär seal the door. He enters (M8) as Mav is sweeping up the silverware. 

Perception: 19

‘Hmm...’ he says, going over to the mysterious chair for a closer look...

Investigation: 11

"Well, no books in here.... just an odd number of chairs."  Isa starts moving towards the door.

"Six for guests one for the attendant." Says Emporious upon noting everyone's fascination with the seemingly extra chair. Seeing no bookS he leaves the room to wait in the hall.

Orvok, seems like a regular chair, just pushed aside into the corner.

Orvok leaves it for now, heading back to join the others outside. ’Next room then..?’ he asks as he closes the door behind him, before moving onto M6...

M6 - THE KITCHEN

The aromas of cooking permeate this kitchen. A large iron stove takes up one wall, and the rest of the room is filled with large tables and racks lined with hanging pots, pans, and cooking utensils. Everything is sparkling clean.

Two homunculi wearing comically large chef's hats greet you as you enter. They startle visibly, dropping utensils and such. "Guests!" one of them shouts. With a flapping of wings, the two small forms land on the nearest table. They bow low before you and ask, “How can we be of help to our honored guests? Cooking? Cleaning? Mending your clothes, perhaps?”

"It smells divine in here.....have you two creatures done this?"  Mav leans over a pot and inhales.  "I wonder if Matreous was aware of this place since he was here for two days."

"Oh, actual homunculi in here... they are basically harmless 'slaves', I wonder if they know anything about the books or other things in this mansion." she ponders. 

Isa holds up the book with the letter I on the spine "Do you know anything about these books?"

Emporious places a cautioning hand on Mavshoons shoulder. "Until we discern the exact cause of Matreous' fate I'd refrain from taking food from strangers. His behavior was odd even before his death."

Looking for books: 24

Thank you, actually, we do need something else. Addressing the one that is not being asked about books, Do you have a Master, and are they 'round?

"Cumin here was created by Fistandia, while I, Coriander, was created by Freyot! We have not seen our masters for quiet some time. We were told NOT to touch books with single letters on their spines. Not know why! Fistandia used to go into the planetarium! Disappear for a long time!"

Mavshoon shoots a side eye at Emprious and pulls a silver spoon out of a pocket and samples whats cooking in the pot.

"The planetarium? Where's that at?" Isa asks. "and who's Freyot?"  Looking to Emporious "Do you know any Freyot?"

"Oh, hey... what do you know of the creatures in jars in the basement or the summoning circle that Fistandia had down there?"

Isa starts to realize how hungry she actually is... seeing Mav take a quick sampling from the pot she inquires "So, what are you cooking?"

Emporious just shrugs ar Mavshoon and responds to Isa, " I haven't the slightest." And to Coriander he asks "Could you show us these books? We're having some trouble locating them."