Shopify Plugin Developer - Rest API & Custom Shopping Cart

I had phase 1 of Shopify plug in done long time back but we never pushed to marketplace or added missing features in phase 2. Now, I am looking for end to end development for all features and polished UI/UX/ plugin developer who can do following things for me - I provide requirements for plugin - for Shopify Marketplace/ Stores - You develop plugin which we will test in couple of stores ourselves - You help me push the plugin to Shopify community/ marketplace Product will have following features at a high level 1) It will be installed as a plugin in my Shopify store 2) It will allow me to select bunch of products or a product from list (SKU?) 3) We will have special screen - Upload Special Deals - My Rest API will be used to push data for SKU, Deal Price, Quantity, etc. Let's say SKU A - $1000 listing price. $950 Deal Price. 4) Shopify store will show my button "ASK FOR A DEAL" where we selected to create a deal for. 5) My JavaScript/Chatbot will be shown when Shopify buyer clicks on that button. You are not responsible for chatbot/Javascript but you will integrate only from my backend 6) My Chatbot will help buyer to select $960 or $970 or $980 price -- Which is above deal price. Call it custom price of the product. 7) We would open Shopify Checkout/ Shopping Cart with a new price - $970 or $973.50 or whatever my chatbot decided for the buyer. There will not be pricing plan for this price at a store level. If we can not have Shopify Checkout use my custom price , we will have our own Shopping cart to charge $975 or whatever and customer will pay us. 8) We will inform Shopify Storeowner that product/SKU is paid for. S/he can ship now.