Either sounds good to me.
Depending on how things go i may expand the story to include more characters at which point existing players will certainly have first dibs!

Im also quite happy for you guys to create npcs pretty much at your leisure. Once our first 4 characters are in I will create an NPC's tab.

If we create an npc we find particularly important or entertaining his creator can just knock up a sheet and i'll add it to the tab. I think the more npcs and detail around the more we have to feed off!