Hello Sam, the UEFN EULA doesn’t specify any particular rights for usage of the Fortnite IP; furthermore referring to this post by Epic regarding Chapter 1 Remake Islands:
“… you are not permitted to create, publish, or monetize content based on others’ copyrighted IP (this is highlighted specifically in Section 4.1 of the Engagement Payout Program Terms). All the seasonal variations of Fortnite’s Battle Royale maps and islands are Epic’s intellectual property.”
So my interpretation of this, which does not constitute legal advice, is that you are not allowed to make any content that depicts or references Fortnite Locations, Characters, Names, etc. This is somewhat confusing given that we are provided so many assets derived directly from Fortnite for use in UEFN but I again interpret their usage as non-infringing so long as they aren’t used to depict or reference Fortnite IP. In my opinion this should be clarified in the “Too Long, Didn’t Read” segment of the UEFN EULA.