This behaviour is correct. Propably, you just didn't set up the template of the page for the new language. Do this by editing the page-properties using the module pages. Afterwards, loading the site in the portal should complete with the desired result.

Yes! You don't have to link to Kajona within your template, not even in the imprint of your site.

The only limitation provided by the licence is, that you don't remove the copyright notes in the source-files (mostly PHP and JavaScript files). Since they are added as comments, they won't get visible to the users.

This error occurs due to a problem with apache, in detail with the apache-module "mod_rewrite". Please try to rename or delete the ".htaccess" file based in the root-directory of your installation.