Sleeping in the same room as a woman with the door unlocked and open plus other ppl staying in the house?
Before getting into the technicalities if it is or isn’t yichud, even if it isn’t yichud, it is a very distasteful, and wholly inappropriate thing to do. There are the halachos of yichud, but there is also the practical aspect of correct behavior, and they should not be sleeping in the same bedroom. Regarding the halachos though, since the situation is taking place at night, there would be a need for another 3 women in the house, or another two men, in order to prevent halachic yichud. If the people in the house are promiscuous, and are not careful regarding the laws of separation between the genders, then there would be a need for even more people.
Rema Even Hoezer 22-5, Dvar Halacha 10-3.