Lore explanation: 

Most of the tall characters are demi-goddess's and half sisters. Born to the Goddess of Wrath which means they tend to have a similar colouration matching a combination of Wrath and which ever Goddess or mortal was her partner that time. The true goddess's are massive giants and are all spawned from the Grand goddess.

The reason why the bigger characters are generally earth tone is because of the lore of their worlds, they are generally demi-goddess's and have a role in protecting those who live within their realms, so the ones with forest colours tend to come from the realm of forest, the darker one generally come from the realm of stars and the lighter cream based ones usually come from much more bright realms like the beach ones, one's with endless rolling yellow grassy fields or one that are less likely to need protection. It's camouflage. 

They ones with the gold teeth generally come from the more dangerous realms and have lost their teeth, that's also why they tend to be scarred more often then the cream demigoddess's.

Also They could totally all have a family reunion.