Using L.Control.Search and L.markerClusterGroup

Question

I am trying to use L.Control.Search and L.markercluster to make a searchable cluster of ~4400 address points. I have tried two separate ways (based on examples I have found) but not yet been successful:

Attempt 1 loaded the address points twice, so the map is uselessly slow and illegible (full link)

    // load address points for address search
    $.getJSON("data/address_pts.geojson", function(data){
            var addressIcon = L.icon({
                iconUrl: "images/home.svg",
                iconSize: [60,50]
            });
            var addresses = L.geoJson(data,{
                    pointToLayer: function(feature,latlng){
                        var marker = L.marker(latlng,{icon:addressIcon});
                        marker.bindPopup(feature.properties.FULL_ADDRE);
                        return marker;
                    }
            });
            var clusters = L.markerClusterGroup();
            clusters.addLayer(addresses);
            map.addLayer(clusters);
    // add search
    map.addControl(new L.Control.Search({
            layer: addresses,
            textPlaceholder: 'Address...',
            propertyName: 'FULL_ADDRE'
        })
    );
    // end getJSON
    });

I wondered if this was some problem with $.getjson, so I tried L.geoJson.ajax extenstion as well:

var addresses = new L.GeoJSON.AJAX('data/address_pts.geoJson', {
      pointToLayer: function(feature, latlng) {
        return new L.CircleMarker(latlng, {radius: 6, fillOpactiy: 0.9});
        },
    });
    var addressCluster = new L.markerClusterGroup({
      disableClusteringAtZoom: 12
    }).addTo(map);
    address.on('data:loaded', function() {
      addressCluster.addLayer(addresses);
    });

    // feature search
    var search = new L.Control.Search({
      layer: addresses,
      initial: false,
      propertyName: 'FULL_ADDRE',
      circleLocation:false,
      collapsed:false,
      textPlaceholder:'Search Addresses',
      zoom:'12'});

    map.addControl(search);

This loads no data or points at all. I assume I was closer to the right track on Attempt #1, but I don't understand how to prevent duplicate loading of the address points.

Answer 1

In the first example:

   map.addControl(new L.Control.Search({
        layer: addresses,

Should have been

   map.addControl(new L.Control.Search({
        layer: clusters,