The sameway you swap the original characters, aka, gentiana, lunafreya, etc into their skimpy/nude version, but to change the boy-band instead swapping the females click the boys instead in short
4. Click "Create New Mod" Choose: Models -> Solo Play -> Next -> Noctis ( Prompto, Ignis, or Gladiolus) -> Next -> Choose Mod Name + Description -> Next -> Create! (or skip naming the mod lol)
same way as before but i remember hal has also the original files created for swapping just visit his website and you should be able to find
