The reason you are getting all of the data in the info windows is because you are pulling the HTML from the "location" div. This div is getting populated with ALL of the data as you are looping over the list of markers.
The quickest way to get this to do what you want would be to add the name and address fields to the anchor tags in your list you generate at the top.
<ul class="markers">
<?php
$markers = get_field('locations', $post->ID);
foreach($markers as $m): ?>
<li><a data-latlng="<?php echo $m['location']['coordinates']; ?>" data-icon="<?php bloginfo('template_url'); ?>/assets/img/map_icons/<?php echo $m['icon']; ?>.png" data-name="<?php echo $m['name']; ?>" data-address="<?php echo $m['location']['address']; ?>></a></li>
<?php
endforeach; ?>
Then you can set the info window content directly in your javascript loop.
$('.markers li a').each(function(){
var $this = $(this),
latlng = $this.data('latlng').split(','),
name = $this.data('name'),
address = $this.data('address');
map.addMarker({
lat: latlng[0],
lng: latlng[1],
title: 'Development',
click: function(e) {
},
infoWindow: {
content: "<b>Name:</b>" + name + "<br /><b>Address:</b>" + address
},
icon: $this.data('icon')
});
});
Now, I would suggest changing the entire design for this to use AJAX calls and have your PHP return an array of JSON data rather than storing all of this data in the DOM. You can use JQuery's ajax function and PHP json_encode/json_decode to pass JSON data to/from the web client.