My own social icons, upfront...

Hello there, I have been of for a while, but upfront is one amazing editor. I have been trying several pagebuilders, but somehow they do not satisfy me. Upfront is the way to go......
Nevertheless I want to put icons in a fixed header next to logo and menu, rather easy to accomplish, but there are little to choose from. How should I put my own font icons in thefont selection window, since there are only a few available. For example deezer, spotify and soundcloud.
I could place a social-widget next to the menu, but it would not act as a part of tghe menu. For example: when the page is viewed on smaller screens, would it be possible to show the icons in a hamburger menu?

Thanks for the great advantages you share,
Frenk