So, Dina and Nina are fraternal (sororital?) twins, yet they have different Zodiac signs. Fortunately, Scorpio and Sagittarius are consecutive (traditionally, though Ophiuchus completely screws that up) so you could explain this as them being born on the cusp. My original thought was that Nina was born before midnight November 23, and Dina was born some twenty minutes later on the 24th. I later realized that I was a day off, and technically Sagittarius starts on the 23rd, but since it's the cusp I figure Nina can still identify as a Scorpio if she wants to. I didn't want to change Dina's birthday because I looked up the metasymbology card for November 24th, and it said this:
This has been called the "Wish Card", and for all 9 of Hearts, there is an intimate connection between money and love. Money may come, or love may come, but the two never seem to work together for any length of time.
Of course, none of this is particularly important to the story, but that made me LOL. Fortune & Romance, indeed.