Any reason not to move this to I18n? Probably we should then remove the files WELCOME-TO-DISCOURSE.md and ADMIN-QUICK-START-GUIDE.md to avoid inconsistency, right?! I would be willing to provide a PR for this.
Also, the title of the Uncategorized category seems hardcoded:
Making more stuff i18n, as well as providing language selection on discourse-setup is always welcome, as long it doesn’t trigger a regression and the complexity isn’t too much.
As it turns out, moving the Admin Quick Start Guide probably isn’t desirable, because it specifically invites to submit a pull request to improve the guide. In this case, however, it might be better to not create this as a topic itself, but rather create a translatable topic which links to the guide.