As always I would prefer original creations but I'm equally truly excited by the news of such collaborations with SNK and AOT franchises! =)
I dont know anything about AoT. But Phase 4's costume isn't that bad. Why wasn't it copied to others? There are three designs here. A bunch with no cape. Some with a cape. And random Phase. I don't get it.
Actually for me she got the best outfit of the pack xD One of the main characters of the work is Captain Levi, considered the strongest soldier against the titans available to the mankind. Despite the character' serious tone and role, from time to time the author like to contrast it through comic reliefs with him, so in a circumstance it's revealed that he is a maniac of cleaning - very likely caused from his childhood passed in an underground city - at the point to force his squad to clean their new headquarter using appropriated "uniforms" as the one worn by Phase:
I could be wrong but from the trailer and the picture it's seemed to me that Hayabusa wear a white cravat - peculiarity of Levi's look - so if this is the case he is cosplaying him in his soldier appearence.