Gists

<?php
/**
 * add labels above facets by changing shortcode output
 * this will apply to all facets except $exclude_types set below
 * change or remove conditional to apply this to whichever facets needed
 * wrapper can also be added
 */
add_filter( 'facetwp_shortcode_html', function( $output, $atts ) {
    if ( isset( $atts["facet"] ) && '' != $atts["facet"] ) { // check for facet shortcode
        $exclude_types = [ 'sort', 'reset', 'pager', 'map' ]; // set facet types to exclude from labels
        $facet = FWP()->helper->get_facet_by_name( $atts["facet"] ); // get facet settings
        if ( !in_array( $facet["type"], $exclude_types ) ) { // conditional to exclude types in $exclude_types
            $output = '<h3 class="facet-label">' . $facet["label"] .  '</h3>' . $output; // prepend with label and markup
            // uncomment below to add facet-wrap
            // $output = '<div class="facet-wrap">' . $output . '</div>';
        }
    }
    return $output;
}, 10, 2 );

/**
 ** adds is-hidden class to facetwp template to initial hide template.
 ** for use with conditional logic addon to show/hide template with
 ** conditions, prevents flash of content when hidden is the initial 
 ** state
 **/
add_filter( 'facetwp_shortcode_html', function( $output, $atts ) {

    if ( isset( $atts['template'] ) && 'my_template' == $atts['template'] ) { // change my_template to match your template
        $output = str_replace( 'class="facetwp-template"', 'class="facetwp-template is-hidden"', $output );
    }

    return $output; 

}, 10, 2 );

<?php

add_filter( 'facetwp_shortcode_html', function( $output, $atts ) {
    if ( isset( $atts['template'] ) ) {
        $output = str_replace( 'facetwp-template', 'facetwp-template row', $output );
    }
    return $output;
}, 10, 2 );

<?php
/** changes <div class="facetwp-template" in facetwp template shortcode output to a ul
 ** will not work if facetwp_use_pager_seo is true
 **/

add_filter( 'facetwp_shortcode_html', function( $output, $atts ) {
    if ( !empty( $atts['template'] ) && 'example' == $atts['template'] ) { // change "example" to your template name
        $output = str_replace( '<div class="facetwp-template"', '<ul class="facetwp-template"', $output );
        $output = substr_replace( $output, '</ul>', -6 );
    }
    return $output;
}, 10, 2 );

<?php
/** add additional classes / id to the facetwp-template div generated by a facetwp 
 ** layout template
 **/
add_filter( 'facetwp_shortcode_html', function( $output, $atts) {
	if ( $atts['template'] = 'example' ) { // replace 'example' with name of your template
    /** modify replacement as needed, make sure you keep the facetwp-template class **/
		$output = str_replace( 'class="facetwp-template"', 'id="masonry-container" class="facetwp-template small-up-1 medium-up-2 large-up-3"', $output );
	}
	return $output; 
}, 10, 2 );