If you plan to try to do the full city and character creation in one session with some people who are completely new to RPGs, I think that part I'd emphasize the most would be the shared story bits of character creation. That way, people will be able to get some idea of how to interact with the world and the other characters via the medium of their character without having to worry about the minute to minute details of a 'live' session.
If everyone has read the books, be able to provide examples of how this would would with Harry, Murphy, and Tomas as PCs. If people haven't read the books, then be thinking of some other media that you've all been exposed to that you can use to demonstrate the same idea.
Next, an explanation of how the rules are mostly interested in producing a 'story' rather than a world simulation. For example, that's why it's possible for you to take a sprained ankle consequence from being shot with a gun. Also, it's why certain 'knot cutting' solutions to things (like, for example, throwing the bad buy off the edge of the building) don't really work in the system. Because having you throw the bad guy off the roof and kill him, round 1, is not that interesting. So, for example, if you try to push the bad guy off the roof,but you don't do enough damage take him out, then he somehow avoids falling off the roof, but he make take consequences that reflect what lengths he had to goto to avoid falling off the roof.