i am not sure where they are location wise.
CH 249 and 250 implies that fiora, creepy, and oscar are at fiora's mansion. "Fiora's mansion? this situation seems strange" and "should I let myself in? there's something wrong with fiora" implying that fiora is inside. Oscar would not know fiora's inside, if they were at the weird house of the evil lady.
but 247 implies that fiora had gone to the lady's house to paint. "did you ask me out here to paint"? 250 also implies that they are at the lady's house since the black cat is there, and they needed it as an ingredient for a ritual.