Actually finally figured this issue out, problem was two template files 
product-images-modal.tpl was missing and there were changes needed to the product-cover-thumbnails.tpl
Not sure anyone will read this but it really really helped to add a comment to the top of each .tpl file with the template name so that when I used Chrome Dev Tools to inspect the code I could see which templates were controlling different sections of the page, like this:
<!-- templates/_partials/breadcrumbs.tpl -->