Thanks for writing in! Sorry for the delayed response. Just for future topics, self responding or bumping your post pushes it back in our Queue system so it takes longer to respond to.
1.) This was done automatically. You will need to design and code the section first and then add a custom function in your child theme’s functions.php file. Take this code as an example:
// Add social sharing icons
// =============================================================================
add_action('x_after_masthead_end', 'display_the_banner_here');
function display_the_banner_here () { ?>
<?php if ( is_single() ) : ?>
<div class="custom-content">
<p>You may add your section here</p>
</div>
<?php endif; ?>
<?php }
// =============================================================================
2.) You are still using X theme 4.6.4. Please update it to 5.2.2 so that it could work with Cornerstone 2.1.3
3.) Do you want something like this http://prntscr.com/gwuzlx? If that is the case, please add the following CSS code in the X > Launch > Theme Options > Global CSS (http://prntscr.com/evui3r) or in the customizer, Appearance > Customize > Custom > Edit GLOBAL CSS
4.) This is called infobar. You can install ConvertPlus plugin by going to X > Overview > Extensions. To know more about this plugin and how you can create an infobar, please check this out:
6.) If you are using cornerstone for each of you post, you can easily insert an Author Box element to display something about the Author.
And if you want something that is automatic, you may use a custom code adding the authorbox shortcode at the end of the content. You can check out this thread:
7.) The share button comes from a 3rd party plugin called Social Warfare. You can easily install this right in your plugins section.