Do the prompts need to be in different formats? Like, does it need to be a fic and a piece of art/short song/whatever, or could it be two short fics showing the same scene from different points of view?

For that matter, by "separate but related" do you mean illustrating a scene right out of a fic that's the other half of your entry would be fine, or do they need to be more separated than that (both being based on the same theme but not directly connected to each other or whatnot)?