Setting up a DFRPG game is intended to be a very collaborative process between players and GM: the Setting, Threats, and NPCs are created first; then players create characters, with backgrounds linked to each other, the setting, its Threats and its NPCs.
But for a single-shot convention game, it makes more sense to create these things in advance. Or is it?
If you were hypothetically going to sit down for 6-8 hours for such a game:
Would you want the collaboration, or would you prefer to be handed characters and go?
Or some hybrid where you get to choose a few customizable Aspects or other elements?
Would you play ball if a GM had predefined relationships between characters? Or would you insist on hashing those out before play?
How do you feel about starting this single-shot adventure in media res, backfilling relationships and other details as the game progressed?
For reference, my gaming community tended towards wanting a predefined City, Setting, NPCs, and Scenario.