About the StreetPass Map:
At first, it wasn't showing up for me. And I already had ~250 people in my plaza. A good amount were actual StreetPasses, and the rest were from Mario Kart 7. But still, no map.
After doing some online races in MK7, I went back to the Mii Plaza. Lo and behold, the map showed up. Oddly enough, it only showed the regions of the people I just raced. I'm guessing it doesn't have a way to check through the previous Miis, so it only checks ones you've met after the update.
Nope, it showed people from all the regions I had met before.