Hi,
1. If you want to add options to the menu items settings, you can edit the view files of the view "menus" for your backend template via the menu Display>Views and add your HTML there.
Then, you can override the frontend view files of the "product" view for your frontend template via the menu Display>Views and use the data of your extra options to change the display of the products.
So you have total control on how to customize the settings and the display of the listings.
2. We don't allow you to access everything there because people messed with the demo website and tried to hack it. So we had to restrict the access, unfortunately. Remember that most templates or extensions demo websites don't even give you access to the backend at all.