Hi & welcome!
I like your lighting in general. 2 & 5 have a great epicness potential, especially with this kind of angle. Since you have to show more or less the whole body, maybe you can mix 1 or 2 with the middle one on the bottom row.
As for the costume i would say the simplest with the biggest area of color so that it will neither spoil your lighting nor too much time-consuming to draw.