Nice work man. Felicia one looks a little off, but I can't pinpoint which thing is throwing me off. I think it just might be her headband and forehead line create a tangency. The girl could benefit from some forehead skin imo. Also, Arthur's looks really good, but his eyes are too far apart, or too small. Adjusting either I believe would fix the off look he's producing. Sakura's nose looks like it could be raised a few notches, but that may just be preference rather than necessity. All just very minor things that don't necessarily need to be fixed, only if you are truly inspired to do so. A diamond could always use a little more shine though. I really like the text used for Akuma's portrait and Roll's portrait a lot. Fits them both really well.
Edit:
Also, Arthur's helmet could use a layer of highlights to further elaborate his shiny metal armor.
by 
(This ins't mine, I just finished it)
Original version 
My version 
