Hello,
1 a. The WordPress theme and WHMCS template are two different systems. There is no internal relation with WHMCS for managing customization from WordPress.
1 b. In this case, you need to customize the WHMCS header based on your WordPress site. Please Note: customization does not include item support. Please learn more about the Envato Market (themeforest) item support policy (item support includes & not includes), here https://themeforest.net/page/item_support_policy
2. Please provide your wp-admin (URL, Username & Password) access using our Envato Market (themeforest) profile contact form https://themeforest.net/user/themelooks#contact (screenshot as reference https://prnt.sc/10o0iwt ) including this support topic link as a reference to review the issue to assist.
4. We are sorry to say that there is no pre-built domain transfer form available. Our theme is all about those features that we have shown in the theme demo.
6. You have another page https://sonethost.com/affiliate-program/ and it has no issue on the mobile menu. Could you please let us know in detail what you have done with https://sonethost.com/website-design/ page
7. Use this custom CSS below.
#mega-menu-wrap-primary-menu .mega-menu-toggle .mega-toggle-block-0 .mega-toggle-animated-inner, #mega-menu-wrap-primary-menu .mega-menu-toggle .mega-toggle-block-0 .mega-toggle-animated-inner::before, #mega-menu-wrap-primary-menu .mega-menu-toggle .mega-toggle-block-0 .mega-toggle-animated-inner::after {
background-color: #000;
}
8. Please check this out https://wpbakery.com/video-academy/use-element-design-options-wpbakery-page-builder-wordpress/
Best Regards,
ThemeLooks Support Team