efuller

It sounds like you might want to utilize categories. Basically, just create your different categories (dogs, cats) and assign each post appropriately.. then adjust your menu to display those different categories.

It appears that the right ‘Sponsors’ sidebar appears further down the page when viewing on mobile.

There are several plugins out there that will enhance this process.

Two of the more popular plugins are:

Custom Field Suite
Advanced Custom Fields

Perhaps use a plugin like Duplicator!

Duplicator

Change the related CSS code in element.css to:

body.handheld .mds-page-section {
    background-size: cover !important;
    background-attachment: scroll !important
}

The background-size could either be cover or contain.

Try putting your conditional inside your function like this:

add_action('genesis_entry_content', 'hello_world');

function hello_world() {
    if( !is_page('about-us') ) {
	echo "<h1>Hello World</h1>";
    }
}

Here are a couple of options you might try:
https://ww.wp.xz.cn/plugins/nav-menu-roles/

Progrommatic approach:
http://www.wpbeginner.com/wp-themes/how-to-show-different-menus-to-logged-in-users-in-wordpress/

Did you go through the process of installing an SSL certificate for your site before changing the URL?

If not, you might restore your database back to a point before where you changed the URL. If you don’t have a backup, you might contact your host for support to help you.