Modifying Comment Form & Comment List along with its Markup

comment_form.php

<?php

//Disabling URL field
function vg_disable_comment_url( $fields ) { 
    unset( $fields['url'] );
    return $fields;
}
add_filter('comment_form_default_fields','vg_disable_comment_url');

//To edit defaults in comment field
function vg_modify_comment_defaults( $defaults ) {
	$defaults['comment_notes_after'] = '';
	$defaults['comment_notes_before'] = '';
	$defaults['title_reply'] = 'Leave A Comment';
	$defaults['comment_field'] = '';
	
	return $defaults;
}
add_filter( 'comment_form_defaults', 'vg_modify_comment_defaults' );

//To modify structure of input fields and the wrapping html markup
function vg_modify_comment_form_fields( $fields ){
    
	$fields['author'] = '<div class="col-xs-12 col-sm-4 col-md-4 form-group">' 
				. '<input class="form-control height-in" placeholder="Enter Name" id="author" name="author" type="text" value="' 
				. esc_attr( $commenter['comment_author'] ) 
				. '" size="30"' 
				. $aria_req 
				. ' /></div>';
	
	$fields['email']  = '<div class="col-xs-12 col-sm-4 col-md-4 form-group">' 
				. '<input class="form-control height-in" placeholder="Enter Email" id="email" name="email" ' 
				. ( $html5 ? 'type="email"' : 'type="text"' ) 
				. ' value="' 
				. esc_attr(  $commenter['comment_author_email'] ) 
				. '" size="30"' 
				. $aria_req 
				. ' /></div>';
	
	$fields['comment_field'] = '<div class="col-xs-12 col-sm-12 col-md-12 form-group top-equal">
						<textarea class="form-control" placeholder="Comment" id="comment" name="comment" cols="45" rows="7" aria-required="true"></textarea>
						</div>';	
	
	$fields['comment_notes_after'] = '<input type="submit" class="btn btn-1 btn-1a ct-us-send" id="submit-new" value="' . __( 'Submit' ) . '" />';
    
	return $fields;
}

add_filter('comment_form_default_fields','vg_modify_comment_form_fields');

comment_form_class.php

<?php

// To add custom class in comment form
ob_start();
comment_form();
echo str_replace('class="comment-form"','class="form-inline"',ob_get_clean()); //class added is form-inline

comment_list.php

<?php

//This will go in place of default comment list call
function vg_list_comments() {
  wp_list_comments( 'type=comment&callback=vg_format_comment' ); //vg_format_comment is the function being called
}

remove_action( 'genesis_list_comments', 'genesis_default_list_comments' );
add_action( 'genesis_list_comments', 'vg_list_comments' );


//To modify comment list and its wrapping markup using vg_format_comment function defined in callback
function vg_format_comment( $comment, $args, $depth ) {
	$GLOBALS['comment'] = $comment;
	$ca = get_comment_author();
	?>
	<div class="comment-details">
		<div class="comment-pic">
			<?php echo get_avatar( $comment, 32 ); ?>
		</div>
		<div class="comment-inner">
			<div class="comment-info">
				<div class="clearfix">
					<h4><?php printf(__('%s'), get_comment_author_link()) ?></h4>
					<div id="reply-cover">
						<i class="fa fa-reply"></i> <?php comment_reply_link(array_merge( $args, array('depth' => $depth, 'max_depth' => $args['max_depth']))) ?>
					</div>
				</div>
				<div class="comment-on">
					<h6><?php printf(__('%1$s'), get_comment_date(), get_comment_time()) ?></h6>
				</div>
				<div class="comment-text"> 
					<?php comment_text(); ?>
				</div>
			</div>
		</div>
	</div>
	<div class="clearfix"></div>
<?php 
}

markup.html

<!-- Comment Form HTML -->
<div class="sub-figure">
	<div class="sub-post-title">
		<h4 class="recent-title">Comments</h4>
	</div>
</div>	

<!-- Leave a comment -->
<div class="sub-figure">
	<div class="sub-post-title">
		<h4 class="recent-title">Leave A Comment</h4>
	</div>
	<form class="form-inline">
	  <div class="col-xs-12 col-sm-4 col-md-4 form-group">
		<input type="text" class="form-control height-in" id="reply-name" placeholder="Enter Name">
	  </div>
	  <div class="col-xs-12 col-sm-4 col-md-4 form-group">
		<input type="email" class="form-control height-in" id="replay-email" placeholder="Enter Email">
	  </div>
	  <div class="col-xs-12 col-sm-12 col-md-12 form-group top-equal">
		<textarea class="form-control" rows="7" placeholder="Comment"></textarea>
	  </div>
	  <div class="col-xs-12 col-sm-12 col-md-12 form-group top-equal">
		<input type="submit" class="btn btn-1 btn-1a ct-us-send">
	  </div>
	</form>
</div>	

<!-- Comments List HTML -->
<div class="comment-details">
	<div class="comment-pic">
		<img src="img/comment.jpg">
	</div>
	<div class="comment-inner">
		<div class="comment-info">
			<div class="clearfix">
				<h4>Vajrasar</h4>
				<a href="#"><i class="fa fa-reply"></i> Reply</a>
			</div>
			<div class="comment-on">
				<h6>September 9, 2014</h6>
			</div>
			<div class="comment-text">
				<p>Lorem Ipsum is simply dummy text of the printing and typesetting industry.</p>
			</div>
		</div>
	</div>
</div>