SearchWP Supplemental Engines with main loop

functions.php

/**
 * SearchWP Query
 *
 */
function ea_searchwp_query() {
    if( empty( $_GET['swpquery'] ) )
        return;
    $args = array(
        's'      => esc_attr( $_GET['swpquery'] ),
        'engine' => esc_attr( $_GET['swpengine'] ),
        'page'   => get_query_var( 'paged' ) ? intval( get_query_var( 'paged' ) ) : 1,
    );
	$tax_query = ea_get_tax_query();
    if( !empty( $tax_query ) )
        $args['tax_query'] = $tax_query;
    $loop = new SWP_Query( $args );
    global $wp_query;
    $wp_query->max_num_pages = $loop->max_num_pages; // for pagination
    $wp_query->posts = $loop->posts; // for loop
}
add_action( 'tha_content_loop', 'ea_searchwp_query', 9 );
add_action( 'tha_content_loop', 'wp_reset_query', 11 );

searchform.php

<?php
/**
 * EA Starter
 *
 * @package      EAStarter
 * @since        1.0.0
 * @copyright    Copyright (c) 2014, Contributors to EA Genesis Child project
 * @license      GPL-2.0+
 */
global $ea_search_settings;
$args = wp_parse_args( $ea_search_settings, array(
	'action' => home_url( '/' ),
	'engine' => false,
));
$s_name = !empty( $args['engine'] ) ? 'swpquery' : 's';
$value = !empty( $_GET[$s_name] ) ? esc_html( $_GET[$s_name] ) : false;
?>

<form role="search" method="get" class="search-form" action="<?php echo esc_url( $args['action'] ); ?>">
	<label>
		<span class="screen-reader-text">Search for</span>
		<input type="search" class="search-field" placeholder="Enter search terms…" value="<?php echo $value; ?>" name="<?php echo $s_name;?>" title="Search for" />
		<input type="hidden" name="swpengine" value="<?php echo $args['engine'];?>" />
	</label>
	<button type="submit" class="search-submit"><i class="icon-search"></i></button>
</form>