@Are Gjertin Urkegjerde Halland - According to the Brand Center help center article, the font will default to Open Sans, but I don't see any mention about the carrying over of colors. My gut feeling is that the colors would carry over, but would, of course, not be available in the template recipient's palette. 

I also see a note in the help center article that, for accessibility reasons, some brand colors may be "adjusted". 

From the help center article:

Great, thank you 

Thanks for the question, @Are Gjertin Urkegjerde Halland! @Robert Johnson is correct! As part of the Miroverse publishing team, I can confirm that custom fonts will default to Open Sans in a template. If you’d like to apply custom fonts, you’ll need to add them to your template as an image. Colors will carry over. 

Something to consider is that, from a user perspective, some may need to alter your fonts and/or colors to fit their own organization’s branding, but I also understand the value of creating content that represents your own brand. In the end, it’s up to you.