How to display multi-value checkbox comma seperated or CSS

I have a Real Estate Website

Please can you tell me how to display items from a multi-value checkbox correctly;

In cmsAdmin, I use a field called 'features' set as multi-value checkbox and let's say someone checks the list of items like this:

[x] item 1
[x] item 2
[ ] item 3
[ ] item 4
[ ] item 5
[x] item 6
[ ] item 7
[x] item 8

In listingDetail.php I put in

<?php echo $listing['features'] ?>

and it would display the results like this:

item 1 item 2 item 6 item 8

I have two questions,

1.  What would I put in listingDetail.php if I want to display them like this (comma separated):
   
   item 1, item 2, item 6, item 8
   
   

2.  Ideally I would like to use CSS which displays icons, copy of the html on how I would want it to look after it had been processed below:-

<span class="features">               
<span class="color-green"><i class="fa fa-check-square-o"></i></span>item 1 
<span class="color-green"><i class="fa fa-check-square-o"></i></span>item 2 
<span class="color-green"><i class="fa fa-check-square-o"></i></span>item 6
<span class="color-green"><i class="fa fa-check-square-o"></i></span>item 8
</span>

What code would I put in listingDetail.php if I want to display the items like the above?

More Information:

At the top of my listingDetail.php file I have the following code:-

<?php
  /* STEP 1: LOAD RECORDS - Copy this PHP code block to the TOP of your page BEFORE anything else. */
  require_once "init.php";

  list($listingRecords, $listingDetails) = getRecords(array(
    'tableName'   => 'listings',
    'joinTable'   => 'homepages',
    'where'       => whereRecordNumberInUrl(1),
    'limit'       => '1',
  ));
  $listing = @$listingRecords[0];


  if (!$listing) { print "Listing not found!"; exit; }

?>

 
I have spent hours on this so any help appreciated.

Thanks
Andy