shopify developer for making wordpress plugin to shopify app

Hi there, I have a WordPress plugin that call external API and show the response to WordPress site. The response is html content so its just need to show on frontend. The WordPress plugin is simple JavaScript code that send ajax request. there are few minor features as well. SO I want to make a Shopify app with same working functionality. The Shopify app need to do these things: 1. add the provided JS script code to each page of Shopify frontend. 2. JavaScript code will send ajax request and embed the html response to Shopify store. 3. make two field CRUD in admin panel, (two simple text fields that will save config for the API call). [login to view URL] apply provided coupon code for discount on checkout process 5. send the cart information to the same API once user checkout. This is very simple for Shopify developer, please if you are not aware of shopify development process and do not know how to create app, publish them on shopify market place then do no waste my time. I am open to discuss budget and time. Thank you