✓ ISSUES WITH UPDATE

If you can provide us WP Logins to your website with URL then we can take a closer look at it. Make sure you set the post as private reply so that only admin can see your wp-logins.

Solved your problems.

For the Sub Header background to be transparent:

Replace this

#subheader {
  background-color: #D7212E;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.4);
  padding: 30px 0;
}

with

#subheader {
  background-color: #D7212E;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.4);
  padding: 30px 0;
  opacity: 0.6;
}

in your style.css file.

Yes, you can add custom sociable icons. Follow this path, victoria/framework/admin/admin-interface.php and find this function atp_admin_head and add your custom icons in that sociable array.