Hello,
1. As I can see, pages on your site were created using Elementor, so the WPBakery can be disabled via Dashboard > Plugins.
2. The editor can be selected during the demo content installation, for example – http://prntscr.com/tgaf9f
All these demos are based on WPBakery – http://prntscr.com/tgafuf https://preview.themeforest.net/item/xstore-responsive-woocommerce-theme/full_screen_preview/15780546 , and these demos – http://prntscr.com/tgagag on Elementor.
3. We would recommend using our Theme Options > Header builder. Elementor – Header, Footer & Blocks plugin can be disabled on your site. If you want to create footer content using the Elementor, just enable it for static blocks – http://prntscr.com/tgah6i , for example – https://xstore.8theme.com/elementor/demos/organic01/ http://prntscr.com/tgahqr http://prntscr.com/tgai25 http://prntscr.com/tgai5r http://prntscr.com/tgai8g http://prntscr.com/tgaicb
Regards