Hello, @Wade Yang,
1- Yes, some of our customers use Uber menus. In this case, you will need to disable our theme options for the menu (Theme Options > General > Theme Menu Options see the image: https://postimg.cc/zVts3K0R) and use the uber menu shortcode inside the HTML Block header element see the image: https://postimg.cc/RqG8bwrb to display the menu.
2- Just like you set the uber menu for the desktop using HTML Block just like this you can add the menu in the mobile menu by enabling the HTML blocks option in the mobile menu: https://postimg.cc/gnZV6PKq
Regards 8Themes Team.