Instead of loading full FontAwesome in memory you can use Sciter's inline vector images.

Steps to convert FontAwesome icons to inline vectors:

  1. Grab needed icon from one of normalized FontAwesome SVG files from here: https://github.com/encharm/Font-Awesome-SVG-PNG/tree/master/black/svg
  2. Copy content of <path d="..."> from the file.
  3. Add "path:" in front of it.
  4. And use it as a URL in <img src="..."> or back/foreground-image: url(...);
Examples:

ambulance.svg