How to replace Home Section 1’s background image with Backstretch slideshow in Parallax Pro

@Grant, Not sure if I am answering your question since, it appears that the backstretch is on all pages/posts in AgencyPro but here’s what I did.
And, unfortunately, my client decided on something different so I took down the code. But, what I remember is the following:
In the agency-pro/js/backstretch-set.js file this is the original code for Agency-Pro 3.1.1 :

jQuery(document).ready(function($) {
$("body").backstretch([BackStretchImg.src],{duration:3000,fade:750});
});


Using Step 3 in Sridhar’s example above as a guide, I changed the backstretch-set.js code to the following, (Of course, replace the http://… with the url to your images):

jQuery(document).ready(function($) {
var images = [
'http://...',
'http://...',
'http://...'
];
$('body').backstretch(images, {duration:3000,fade:1500});
});

Make sure there is no comma after the last image.
I believe that’s all that was needed to make a backstretch slideshow for Agency-Pro.
Of course always make a backup and use the code at your own risk.
Cheers.