Like many others, I’ll do a debrief for a one-shot, but never for an ongoing campaign. I find for a one-shot players may want to know simple things like “did we miss any clues?,” that type of thing.
Spitballing a couple ideas. How about the drawing of the cards and her readings are unknowingly influenced, perhaps by a trickster type like Nyarlathotep or entity from the Dreamlands? Or perhaps she finds a “special” deck of tarot cards that are actually a “Mythos Tome?” (Could be a great prop opportunity.)
Both look great. I have tentative plans to run A Cold Fire Within at some point, so looking forward to checking that out. The Dead of Winter will be a nice bonus though for sure.