I’d really love a tutorial on how to include custom Bootstrap themes such as these in Firmasite.
Did you check http://theme.firmasite.com/child-theme/?
I looked into your themes folder and noticed that those themes (BootSwatch themes like Amelia, Cerulean etc.) are all simple css files, whereas these admin themes are complete templates with a bunch of assets of their own, so I’m guessing it’s not quite as straight forward as dropping a folder in the right place.
Bootstrap’s css is just 1 file which is enough but its minimum requirement. No one is stopping you to add additional css files or new php/css/js components. You can think FirmaSite as a main clean theme that supports additional features on child-themes. For example i am working on a premium real estate child-theme that is using FirmaSite as main theme 