Lead Developer
Font Awesome is already supported in menus as long as you don’t have a plugin installed preventing it from working.
The others would involve some somewhat hacky things to be added to the code, so I wouldn’t put that into the code. However, you can always find the code by Googling “allow html in xx title wordpress” or something along those lines 🙂
Documentation: http://docs.generatepress.com/
Adding CSS: http://docs.generatepress.com/article/adding-css/
Ongoing Development: https://generatepress.com/ongoing-development