Header Button Arrangement

You could do this:

.header-menu-nav-folder-content
{justify-content: initial !important;}

.header-menu-nav-folder.header-menu-nav-folder--active {
    flex-direction: column-reverse !important;
}

Sadly, it does move the Social Icons above the navigation.

You could do this approach instead to solve that issue:

.header--menu-open .header-menu .header-menu-cta
{order: 0;}

.header-menu-nav-folder-content
{order: 5 !important;}

.header--menu-open .header-menu .header-menu-actions {
    order: 6 !important;}