Hi, I have experience with pixel to pixel HTML5 designs, also with W3C standard code, XHTML, CSS3, CSS, SASS, LESS, javascript, jquery, ajax, jquery plugins, responsive design with bootstrap and web browser compatibility (chrome, opera, safari, ie, firefox, edge).
I can develop the code to read the json file and show the client the products, when clic on one product will show the childs items. The final result will be only with HTML/CSS, using ajax, javascript and jquery as you requested.
Please contact me, I'll be online.