To do this:
Fortnite the game would have to shift to skeletal with (default graphics) as the [display graphics] over the skeletal objects/map.
*Thus being skeletal, you will be able to shift graphics accordingly. Kinda like skins/outfits 
Unless the map and such are skeletal already 
Hope this helps or sounds cool
#Absorb Every Game
#Rated (E → M) Graphics? 
*Could change Fortnite’s Rating from T for teen to rated [E → M], or [E → T] is what the game rating should currently be because of all the rated [E] Game Modes
**Here’s a post of why and how Fortnite can change their game rating to [E → T], which could also lock down Graphics Packs and potentially shift Fortnite’s game rating to [E → M]