EDIT (16/11/2018):
This awesome website published an amazing recent article regarding this question right here made by me several weeks ago. It was the first time that someone had made such detailed map over there, with all creatures location being specified, rather than a simple list of what exists there:
https://www.tibiaexpedition.com.br/maze-of-lost-souls-mols-tudo-sobre-o-labirinto-das-almas-perdidas/
First Floor of MOLS:
Second Floor of MOLS:
Third Floor of MOLS:
Fourth Floor of MOLS:
Curiously, the work made by this fan concluded that even the two biggest wikis existent today are lacking some monsters mentions! Both biggest Tibia wikis aren't citing the Orc Spearman on MOLS, and also the mention of the creature Wolf isn't being exhibited on the Brazilian Wiki!
The article is amazing, filled with information that I never saw being actively discussed anywhere else. The images above answered my question, but I invite you to check out this big article!
Apart from what is mentioned about creatures mysterious places and locations were discussed. as I asked it in order to understand the basic of it, I can highlight that it is mentioned about the several small stones there scattered around, several stalagmites and the presence of the water on the cave, the "big energy bomb" trap, the mysterious magic wall, the two human corpses that cannot be reached, the bodies of dead trolls and the another famous basket with the note mentioning about playing a flute for snake enchantment (this one is my favorite mystery). There is no conclusive answer on what these things can possibly mean (if they mean something at all), but I found very nice to see all of these interesting mysteries reunited.
By the way, the creator of the fansite above also showed the Treasure Room that I questioned. Very cool to see it finally! I literally have no idea if I had seen this before!
Congratulation @Orothrez for the amazing exploration done!!!
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https://tibia.fandom.com/wiki/Maze_of_Lost_Souls/map
Well, here is a good map about the whole place, but without any specific location signaled. It also includes Demona location. Guiding there can be troublesome. I would say that going with a friend covering the place with you can surely help. More detailed marks and tutorials should be done there, appointing mysteries, allusions and correct monsters locations there.
https://tibia.fandom.com/wiki/Maze_of_Lost_Souls
Here is the list of powerful creatures available there. You can find two Dragon Lords over there as well. They are interesting to face if you want an easy Respawn without many people around. Probably it got even better to hunt there with the permanent increment on Respawn speed on Tibia, and also it can be lightning fast during the Rapid Respawn Weekends.