Take our apologies for the delay in answering.
1) I don’t see the mentioned issue on your site anymore https://prnt.sc/1syesnu
2) Set the mega menu for the menu item https://prnt.sc/1syf6ee if you want to use Static block mega menu inside
3) Image changed as I can see https://prnt.sc/1syfdna
4) Add the Mailchimp shortcode https://prnt.sc/1syfijc to the footer content https://prnt.sc/1syfl26
5) Categories select displays all the product categories with products that you created in Products > Categories. We don’t have option to exclude categories from that select. You can only enable/disable search by categories in Theme Options > Header builder > Search > Search By Category
6) As I can see you have sorted out https://prnt.sc/1syg581
7) Edit the mobile header and bg/text color settings of the headers areas https://prnt.sc/1sygn15
