
Oh, the halo was not an element I had delved into and now it feels like an oversight. Definitely going to look into that the next time I work on this.Bill G. said:
It's really hard to do justice to in a static sketch, but your mention of Mercy (and the other angel imagery I collected on Pinterest) got me thinking. If this were an animated show, I'd have her wear a necklace or neck ribbon. When she transforms, a holographic ring would spring out of it, travel up from her neck and across her face, and wind up as a halo over her head. The ring would transform her face as it passed up over it. This, but a halo rather than mask and up rather than across.
Every other observation is fairly spot on to my own thoughts while designing them.
[Note: I started writing this at like 9am this morning, left it up when something else grabbed my attention away, and then suddenly saw that I hadn't actually posted the reply. That has been my whole day in a nutshell.]