kdupont

Add a child theme an in the style.css file, add the following:

.site-header .site-branding {
background-position: 0;
}

Under Appearance -> Editor look for the custom-header.php file.

There is a group of code that uses css to manipulate where the logo is placed. (see below)
Remove the 50% next to background-position:

<?php if ( ! empty( $header_image ) ) : ?>
.site-header .site-branding {
background-color: transparent;
background-image: url(‘<?php echo esc_url( $header_image ); ?>’);
background-position: 0;
background-repeat: no-repeat;
height: <?php echo absint( get_custom_header()->height ); ?>px;
}
<?php endif; ?>

Under Appearance -> Editor, you will see a list of files. The content you seek is located in the Theme Functions.

It could be that a plugin is responsible for creating the child pages (ex. ecommerce plugin would have a store, checkout, products). Once you disable the plugin, the pages will be removed.

Also check to see if your Menu that is being displayed is the default menu or if you created your own. If you created your own, you will have to go back and remove the pages from the menu. That will have the pages disappear from the menu.