Perhaps you should take a look at this. This might clear things up. ^^;
As far as I know, though, Touhou's still going to go on for a while, even if ZUN stops working on it (whether he will or not I don't know, but it doesn't seem like he will stop). The fans might very well carry the series in perpetuity. That's how I see it, at least.
Yes, I never suspected him really stopping, although I do wonder how long this will continue. After all Touhou is somewhat like a red line that is drawn through his life since he started studying. Also, that thread is really funny.
Here`s what i found.
not sure if Double Dealing Characters is about Tarot cards?
Mh, but for that the mirror seems to be too important, since mirrors can have really deep meanings? Your guess isn't bad, though. Maybe both play a role. It would even be possible, if ZUN had implemented alternative routes in this game like he had in HRtP or IN. After all ZUN had written that the characters could either, stick to their weapons or abandon them - Maybe it's presented in form of a path select choice after stage X and depending on which choice is being made, the mirror or the tarot cards get more meaningful in the later stages.
The mirror would probably be important when the character sticks to her own individual weapon and then has to face off the youkai that is possessing it. Abandoning the weapon would lead to an alternative path in which the player meets the fortune teller you mentioned - Probably telling the character that she will choose the other path (making it a bad and also silly ending which ZUN is known for implementing).
Just tossing out some speculations here. :getdown: