Thanks a lot everybody for the contributions to this discussion!
Your recommendations were all useful to better understanding the plugin and finally realise a prototype against 10Duke.
I've embedded the forum into the iframe of my website and am currently using Facebook SSO. However, whenever I try to log into Facebook, it redirects me to the Facebook page then to my nodebb website after signing in. Does anyone know how to make the Facebook SSO redirect to my website or have the FB login be a popup window?