I have some ideas
Maybe the inkla lived among humans for a time, but weren't exactly "loved" by them, and were eventually hunted down and enslaved to near extinction. It fits with current lore, and shows that inkmatas wasn't the only inkla slave.
Draconics I imagine mainly lived underground, and were likely involved in hunting down the inklas. Idk much about draconics, but I think this fits with the whole hating other races theme
Merfolk I think would've been rather neutral, and didn't get involved with the chaos on dry land much.
As for dryads you could try and add some terraria lore, after weakening Cthulhu, forcing him to retreat to the moon, the dryads were greatly weakened. Leaving only a few left. These last few dryads were likely hunted down by humans and draconics, leaving only nata left. I thought this would work well since nata is (at least inspired by) the dryad from terraria