Hi Emre,
Please find my answers below:
1. We will update structured data in the next version of the theme. But in the meantime you can overwrite the function “afftheme_structured_data_review” (prp-functions.php) in your child theme and make the changes you want.
2. From the screenshots I can understand that you have enabled “Review single templates” from Theme Options.
So you see the single template of the theme, this is not a shortcode, it is a specific template.
In order to use a different view you need to use pages and add the shortcodes you generate with the layout you want.
3. The close button is on the top right corner when you open the search lightbox.