FacetWP – customize EDD Coming Soon label

<?php

function fwp_index_coming_soon( $params, $class ) {
    if ( 'cf/edd_coming_soon' == $params['facet_source'] ) {
        $params['facet_display_value'] = 'Availability';
    }
    return $params;
}
add_filter( 'facetwp_index_row', 'fwp_index_coming_soon', 10, 2 );