Fortnite definitely uses DFAO, but I thought it also uses DFGI. It’s has to be all dynamic lighting due the player building things, do you think it would look so good without any GI? Epic has DFGI, and the rest of Fortnite graphics is pretty simple, so I don’t see any reason why they wouldn’t enable DFGI on Ultra settings for those running a GPU like a 1080 ti.
HFGI is not used by any Epic project that I know of apart from the kite demo. And as you said, its broken.