Gotta say, if you're looking for freebies, you might be better off being up-front about who the client is and what game they're developing - if only because there are very, very few titles in the NSFW arena with brand-name recognition and it's easy to make claims like that if you don't have to back them up. Since you're a team member yourself and not a recruiter, I can't think of any obvious reason not to share these details. If it's genuinely a recognisable name that people will have heard of and played, then it will only work to your advantage to name them, as fans of the series (who likely know the characters and story arcs already - another advantage) are likely to be more interested in contributing.
I also can't help wondering how unpaid interns will help 'professionalise' things. If you want professional, you need to hire professionals.