Yes, dots are bought and therefore it can be used as a private scene.
Keep in mind that each Sanctum can only be used for one scene at a time - but the Mysterium meeting is about to be closed anyway (
hinthint, nudgenudge).
Belle, es hinted at in TH - analyzing the Artifact is 30 minutes per roll, so it's really more suited for a solo scene, unless you want to just prepare with all your tools
The ghost is not always manifested, but for the sake of Corn's storytime we can assume her being there, looking longingly to the distance and seldomly reacting to outside stimuli.
Feel free to tag me if you need anything!