Is it possible to add your own fonts and use them with the included plug-ins, if possible how would I go about doing this?
you have google fonts tab in general settings
We have our own fonts, which are not open-source and not included in google fonts that we would like to add.
they are part of the theme ?
No, they're added through a plug-in called "use any font", which allows us to host our own fonts.
you can edit the css of the plugin and call the font family - do you know css ?