The Winged Nightmare is meant as a 'generic' profile to describe Hunting Horrors, Flying Polyps, and all variety of airborne eldritch beasties. Dark Young is one we probably won't ever do anything official for, as we've generally limited our scope to Lovecraft's own creations. I'd consider it a Formless Thing for game purposes.
Also, remember that you can always buy additional skills to modify the profile as well - up to five per Lurker model. That allows for a great deal of 'personalization'.