How do you find out how many people in a spot have medals for that spot?

Count them.

Or set up a pick asking, if there isn't one already, and hopefully most people with medals will respond and respond honestly.

With all content you can see which user added it. If that person has a medal in that spot, a green/yellow/red dot will appear before the users name. That way you can see who has a medal in that spot. However there is no list or anything to see who has a medal. But usually it's pretty clear who has a medal in a certain spot, because they're very active.

Hope this helped!

I've been wondering the same thing.

On a spot, there is a little bar down the bottom with a few fans on it. On the spots that I have contributed heaps on I'm always in that bar and so are the other fans who've done the same thing... But they're re-ordered a little each time... I was wondering if that has anything to do with medals.