speculation is fun! What happens if you're wrong really? :D
I'd go with a Taki replacement and Raph tho'
(I think he looks wilder because 17 more years of being corrupted will make you kind of crazy~ Also the female's pose is very reminiscent of the Taki over the shoulder sword but without the weapon, but has a much younger look*)
*Yes thats a lot to draw from an outline, but what the hell ;)
Looks like Raph to me.
Female, I'm shooting for Tira or Talim. She's not holding any form of weapon, so I'm not saying just based on the
stance it's Taki, especially since the look of the outfit isn't really anything like what she's been portrayed as previously.
This is my bet:
1.- The Male Silhouette is a new character but is a cursed human as Rafael and use a weapon similar to the rapier.
2.- The Female Silhouette is a new character too... but has the personality of Tira with a new weapon (more real and no like the death ring of Tira)
3.- Probably the female silhouette is Tira, but totally sure the male silhouette is a new character.