Hey there!
Regarding the excerpt, add this function to your functions.php file and then call it within the loop from your code like this:
<?php
function my_custom_popular_posts_html_list( $posts, $options ){
...
// loop the array of popular posts objects
foreach( $posts as $popular ) {
...
// Excerpt
$excerpt = '';
if ( 1 == $counter ) {
$excerpt = get_excerpt_by_id( $popular->id );
}
$output .= "<li>";
$output .= $thumbnail;
$output .= "<a href=\"" . get_permalink( $popular->id ) . "\" title=\"" . esc_attr( $popular->title ) . "\" class=\"wpp-post-title\">" . $popular->title . "</a>";
$output .= $excerpt;
$output .= "</li>" . "\n";
$counter++;
}
$output .= '</ul>';
return $output;
}
add_filter( 'wpp_custom_html', 'my_custom_popular_posts_html_list', 10, 2 );
About the thumbnail, you could just add the style to the image tag directly like so:
$thumbnail = "<a href=\"" . get_permalink( $popular->id ) . "\" style="padding-bottom: 7px;"><img src=\"" . $thumbnail_src . "\" class=\"wpp-thumbnail wpp_cached_thumb wpp_featured\" alt=\"" . esc_attr( $popular->title ) . "\"></a>";