I think that I'm being misinterpreted, I'm not suggesting that the favor quoins at each location are for different Giants, I'm saying, maybe each location is representative of one of the Giants.
The Abysmal Thrill quoin actually gives +100 to all of the Giants.
I'm sticking with the favor coin as the best way to correlate location to giant. Still, some are missing and others over-represented (geez, Cosma). Arbor Hollow is probably Spriggan and Sky Plunge is probably Friendly 'cause it's so fun to do drunk. I bet there will be lots more of these in every delicious giant flavour.