Ok, then I'll restart the game. Or I'll just wait for some weeks with my first "serious" playthrough.
That's a fantastic idea with the on-off background characters! A little bit of life in the town would be great for the atmosphere. And I find this percentage-solution a good idea to make it more believable - I'm actually really surprised that this simple but effective idea isn't used more in games. It definitively enhances immersion if there are not always the same characters standing at the same spots.