My guess is that this whole thing is a ritual cycle. The monstrous Kiwako is a former caretaker herself, as we just saw in this chapter. So whatever they are doing in that mansion will end up in a "sacrifice" where one of the caretakers is magick'd or whatever into that ghoul-like being. For one reason or another the ghoul will die on her own after some time hence the constant change of personnel and the ghoul's name, because the agency has to constantly look for new "vessels". Hikita and Kumakawa are weird as fuck because they've seen a lot of that shit but for some reason were never chosen to be the ghoul. As for why they bother converting these women into ghouls - I honestly have no idea, but it might be a cult.
And from Kumakawa's actions in this chapter, I'm starting to see her in a new light. The way she tried so hard to get Akane fired might be her attempting in a roundabout way to save her from being the next vessel, because it's pretty obvious now that Akane was only hired exactly for that. Her room was Kiwako's old room, even. Perhaps Kumakawa saw a bit of her old self before all this shit in her or something.