I think some things on the FAQ page are outdated:
<< Will I be able to migrate my forum to Flarum?
Yes, but not for a while. Our focus right now is on getting Flarum stable and feature-complete. Once we’re confident that Flarum is ready to be used in production, we’ll start building tools to import data from other forum software like esoTalk, FluxBB, phpBB, and others. >>
There is at least a phpBB importer, https://forum.kaosx.us used it and it works fine for it, with the only one regression that URLs didnt get ported back then.
<< How do I translate Flarum into my language?
We’re currently working on documentation for the language pack creation process. We kindly ask that you wait until it is ready before attempting to translate Flarum. Thanks for your patience! >>
https://discuss.flarum.org/t/languages