Customise Wordpress Theme with 3 x Extra Functionalities

Our client requires the use of a Portfolio functionality on their Wordpress homepage with filterable categories. We require the following custom features: 1) Add fixed images in between Portfolio posts. In between some of the portfolio posts on the homepage, they would like to insert a jpeg image. (Pls see attached image- the white sections A & C) These images will stay fixed and will not move, even when portfolio posts are filtered by category. We will be using a built in Portfolio in the theme. Its called Bridge by Qode Interactive [login to view URL] We would like to add any Custom JS script code into their Dashboard- Qode Options- Custom JS field. Ideally, we dont want to have to regularly update the code ourselves. We hope it can sit in Custom JS field and we wont have to touch it when it comes to theme updates. 2) Portfolio Posts Order Randomised. Whenever visitor comes to homepage, the Portfolios order must be randomised. We will have 5 categories, 2007, 2010, 2012, 2013, 2016, ALL. If they click on 2010 for example- the Portfolio will be filtered to display only 2010 portfolio posts, but they must be Randomised as well. When you click on ALL category, the Portfolio post order will be Randomised again. 3) Return from Lightbox, Portfolio Order Randomised again When visitor clicks on any portfolio thumbnail, a lightbox image will appear. (This is already built into theme) When visitor exits the zoomed in Lightbox, the order of the Portfolios are randomised again.