As a matter of fact, that headline convinced me that you're probably one of the worst FashionFramers.
As in, even worse than the Pink Rhino with Titania Idle-Cult.
But to answer your questions;
Darker Colors with a Bright energy color usually work. Black, Dark Blue, Silver maybe. As for energy, Yellow, Orange, Blue, maybe White or a light pink. Those work pretty okay.
Then again, Banshee's - in mythology - are basically dead. Ghosts. Something among those lines. You could try to find inspirations from pictures on google:
I think I got some old screenshots around somewhere...
There's no "no armor" options, since most Frames have none to begin with.
But you can use other armors instead. Something subtle to give her a symmetrical look.