>>528350125
It's the same armature. I made a custom body years ago using a base body from the save the world files, so the weights on the body match the Fortnite skeleton.
At the time when I made it, it was just because I thought all of the existing available models looked like shit because Daz bodies don't stylistically match Fortnite. The animation compatibility just ended up being a fun bonus when they started making sexy dance animations as emotes.