Nothing changes when you click those links because links aren’t written for those icons, they have only “#” symbol for urls if you noticed.
To remove other icons edit the file wp-content/themes/royal/headers/parts/top-bar.php.
1. If you want to have multilingual site you need use WPML plugin http://wpml.org/ .
2. Yes, the changes will be lost when you update the theme. So to keep them you need make changes in a child theme http://codex.wordpress.org/Child_Themes . Create the same directory hierarchy for the file you’re going to edit.
3. When you use wpml plugin to change currency the color will be the same.