Wonder how much that poll is going to weigh in on the decision making process for the roster. Even though those artworks aren't "official" as they say, I really can't help but question why they chose to design those characters specifically. If there's anything made clear to PS, the fans like the veterans and dislike the newcomers. They may not be the artworks for SCVI, but it's possible that they made contact with PS. Does this in any way hint at the roster?
Seeing Natsu scared me when it was thought to be real, but then as I mentioned I noticed how she was using different weapons. Is it possible they know she's coming back and with a new playstyle to separate her from Taki? Nightmare doesn't have a host, which fits in nicely with Raphmare getting killed at the end of SCV. Kilik still has the helmet and has a small beard, so this suggests he's still the old mimic version (unless him holding the staff remains true, unlike SCV). And of course, Sophitia seems to have come back from the dead and sexier than ever. These are interesting choices: one SCV newcomer with a modified style, two returnees that continue the evolution of their past appearance, and one SCV roster cut that remains youthful. All of this points towards them continuing from where SCV left off, but finding ways to bring back familiar faces.
Passion Republic might claim it was for their "internal portfolio", but I have seen speculation that it's more than that, and it's quite convincing too. One of the points made is that they chose to make Soulcalibur artwork, and very convincing artwork at that. Think about it, SC hasn't been relevant in years, while other fighters such as Street Fighter, KOF, BlazBlue, Guilty Gear, and of course, Tekken are currently more culturally relevant in the gaming consciousness than SC, which is a simple fact that I hate to admit. The next point is that they released these artworks at the perfect time, when SC is starting to become active again on Facebook and they are quite obviously generating hype for an announcement. And finally, the choices -- these seem quite 'random' for an internal portfolio. While Kilik, Nightmare, and Sophitia are iconic, they are from different 'groups', while Natsu is nowhere near as iconic as any of them. Most would've chosen people like Mitsurugi and Taki, Nightmare and Siegfried, Kilik, Xianghua, and Maxi etc. They all belong in the same sort of "category", but not here.
It may be that PR has no connection to SC whatsoever and this really is just for their internal portfolio and nothing more. But it's also possible that there's far more than just that, and they're covering themselves to avoid trouble. Whatever the case, we'll find out soon enough.