Add a simple shortcode with options

<?php 
//add shortcode
add_shortcode( 'properties_list',  'list_porperties_func' );
//short code function
function list_porperties_func( $atts ) {
	    $a = shortcode_atts( array(
	        'property_type' => ''
	    ), $atts );
	    ob_start();
	    	require_once(plugin_dir_path(__FILE__) ."/templates/shortcode-archive-listings.php");
        return ob_get_clean();
}
?>
//shortcode-archive-listings.php page
<?php 
	$property_type = $a['property_type'];
?>
			
			<?php $i = 0; ?>

				<?php 

					wp_reset_query();
					$property_archive_loop = new WP_Query( array( 'property-type' => $property_type,  'post_type' => 'property', 'posts_per_page' => '-1')); 
					if($property_archive_loop->have_posts()){
				 		while ( $property_archive_loop->have_posts() ) : $property_archive_loop->the_post();
								//Post variables
								$propertyclas = new propertyListings();
								$post_id = $property_archive_loop->post->ID;
								$metaall = get_post_meta( $post_id );
								$post_count = $property_archive_loop->post_count;
								
								$class_value = $propertyclas->return_class_number($post_count);

						?>
							<?php if($i === 0){ ?>
								<div class="row">
							<?php } 
							?>
									<!-- Row for main content area -->
									<div class="small-12 large-<?php echo $class_value; ?> columns" role="main">	


										<article class="property-archive-shortcode" id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
											<header>
												<h2 class="archive-title"><?php the_title(); ?></h2>
											</header>
											<div class="entry-content">
												<img src="<?php echo $metaall["wpcf-property-gallery-image"][0] ?>" alt="<?php the_title(); ?>">										
												<?php $propertyclas->custom_experct('custom_excerpt_length', 'wpden_more_view'); ?>
											</div>
											<hr />
										</article>

									</div>
							<?php 
								if ($i === 2 || $i === $post_count - 1 ) {
									# code...
									$i = 0;
									echo "</div>";
							 	}else{
									$i ++; 
							 	}	
							endwhile; 
						}//end if else for posts
						else{
							//this only jumps in if no posts where found using the property_type variable....
							$adminurl = site_url() . "/wp-admin/edit-tags.php?taxonomy=property-type&post_type=property";
							echo "<h2>No properties of that type found.</h2>";
							echo "<p>The Correct syntax for the shortcode is </br> <code>[properties_list property_type='PROPERTY_TYPE_SLUG']</code> </br>, A list of property types can be found by clicking the following button:</br> <a target='_blank' href='$adminurl' class='button expand success'>Property types</a></p>";
						}
					
					?>
		<?php wp_reset_query(); ?>


//Then short code call is done like so: