...Now struggling with adding an icon from Font Awsome. :-) ...
 Alternatively, you can use a unicode icon, which is most efficient anyway (because it already exists at the client's browser).  The 6-digit versions are usually in full color.  🎥  
In order from best to worst: 
1. Unicode icons (best--no shipping charge)
2. Fonts (costs a little bandwidth to send them)
3. Base64 encoded icon (very colorful icon is too big, but 16-color icon is okay)
4. Icon files (worst and slowest, because each file makes a separate trip). 
Instead of storing the template as an ANSI encoded file, you can use UTF-8, which is editable with Notepad++ open source editor; And, a UTF-8 can store emoji's so much easier, just copy and paste from 
https://emojipedia.org/   Microsoft Notepad won't do; so, you'd need this:  
https://notepad-plus-plus.org/  (click the Encoding menu) and save your icons directly in the template. 😺