“Tools->Delete Site” menu item is protected by meta capability ‘delete_site’, which is mapped finally to the real ‘manage_options’ capability. Your modified ‘editor’ role has ‘manage_options’ capability. This explains 1) why user with editor role has access to the ‘Tools->Delete Site” menu item.
I made quick test and “Admin menu access” hides/blocks this menu item successfully for the WordPress built-in admin theme. I suppose that User Role Editor is not compatible with “clientside” plugin. Can you deactivate this plugin temporally and look if “Delete Site” menu item will be hidden for a user with ‘editor” role?
I will try to answer on VC and mailgun part of your question tomorrow.