Hello,
Please, never provide private information our of the Private content area! Because then it’s visible for all the visitors.
1) Issue is caused by builder of the WooLentor – WooCommerce Elementor Addons + Builder plugin. If option is disabled https://gyazo.com/0b220cf18c2fe14550d471e6044417d4 everything works fine. Contact plugin author to fix the issue with the double popup.
2), 3) Provide us with link to product where you have the mentioned issue, please. And don’t forget about FTP access to your site if you still have a problem with the gallery and related products after disabling the option of the mentioned plugin.
Regards