If it's asking you for FTP login information when you try to update wordpress or a plugin, you don't need to do that! Chances are you don't have permissions correctly configured on that directory. Make sure apache owns the directory. On ubuntu, this will probably work (depending on which user owns apache):
Mysql-client 5.6 doesn't seem to exist, and you don't need it. Phpmyadmin installs mysql-client 5.5 automatically, and that works with mysql server 5.6. If you're having issues, you probably need to run "sudo dpkg-reconfigure phpmyadmin".