Well the armor overlay is displayed using SBARINFO to show the current armor's icon, and the extra blood details are added in a hacky home-made method based on how the face works. As far as outfit editing goes, I usually just slap down some blocks of color with a pixel brush in the general shape and then add shading later, that makes it easy to keep everything tidy.Just gotta make sure you leave her sleeves off if you want the extra damage levels to be visible (the blood splatters on her chest will be visible regardless)
In relation to arm sprites, unless it's a full-on arm out punch frame i just take vanilla arms, take off the hair, add some extra sinews and detail the gloves (doing this all in monochrome and then recoloring in slade helps). In Stone's case I make her look a bit beefier cuz she's built like a warhammer dwarf lol but for most other female characters it could help to shave off bits at the sides of the arm for a less brawny look.