@Casey-Chen-Lai You'll want to translate to zh-TW, which is our traditional chinese variant.
Don't ask me why it's TW and not HK.
zh-TW is available for translation in Transifex, let me know if you run into additional issues
Is it possible to integrate NodeBB into a cms like keystone, especially sharing the user authentication/management with a cms?
You'd probably have to write an SSO plugin to share authentication. @julian has a ton of SSO plugins that you could use as a sample in writing your own one
As far as user management... somebody was asking for a WP user management plugin. Kind of like if you upgrade a user's privileges in WP, it updates it in NodeBB as well. It's doable but the client didn't end up going for it so we never ended up building it