While getting talent with any name value to do adult work is always a longshot, it doesn't hurt to ask. What gets a "LMAO GTFO" today might be money desperately needed in 6 months. And as I alluded, you can always credit them as "sexythot8847luvzcockxoxoxo" or some such other name if needed. Getting amateurs that can do a reasonably close facsimile of the original that would do it in exchange for the exposure could be an option if the originals aren't interested.
In this case I believe you are misapplying DMCA. If they were to take voice clips from show, which WB does own, and use that without permission, it would be a DMCA violation. In this case they would be hiring the voice talent directly and would own the recording outright, whether WB liked it or not. My understanding of the first DMCA complaint was the use of the term Injustice, which WB has trademarked in ways which overlap the game and thus violated their IP in a way not covered by the porn parody loophole.
To clarify, it's the basics I mentioned that keep me from putting a couple bucks in. Quality (key word: quality) voice acting that sounds similar to the voices from the shows, whether they're the original voice talent or not? I'd pay more for that, especially in the cases of the sexier voices like Lois, Zatanna, Poison Ivy and Roulette.
In a way, I get where SS7 is coming from at times, and in other ways I have no sympathy at all. I occasionally fansub anime, have translated eroge professionally and have helped some Japanese friends with their doujin games in a limited capacity. I'm more particular in my translation tastes. When it's stuff I'm doing on my own time for free, it's a very literal translation, Japanese-styled honorifics/proper nouns and other anal things that appeal to the hardcore crowd, but not so much to the casual. It's also a much bigger pain in the ass that it might sound, so it's something I do occasionally when I feel like it.
OTOH, if you hire me it doesn't matter if I feel like it or not. Once I take your money I get the job done to the customer's preferences, even if I'm not feeling it. There is something about SS7 seeming to regularly go against the preferences of the people financially supporting the project that rubs me the wrong way. At a certain point you transition from being a hobby to being a business (at which point it is no longer about you), and I think that line has been crossed.
In my experience working on eroge (different development engines) adding voices is as simple as clicking the box with the text and clicking a few more buttons to link the audio file to the line. Mindless and tedious, but not difficult. And as mentioned above, the focus is on quality. It's about initiative and vision more than getting Dana specifically to slobber all over my Lexellent dick.
I think I can use my Bible Black black magic powers to do something about the Zee content too.
!!!1!!1!!EEEEER ESLE RO SEITTIT ANNATAZ EROM EKAM
