Complete an unfinished project using PHP and Javascript on Wordpress

Please note: that the majority of code is already written but there are some gaps in the code that need plugging and then implementing. Essentially we have the following requirements: 1) Check Availability - User searches their postcode to check that we provide services in their area (This is already Written) 2) When a user searches their postcode, a modal will appear (this needs creating), wherein they can select their address from a list, based on the postcode they selected. We already have this list and API created. We need you to put this code into the modal popup. 3) When any user searches a postcode, it adds all the returned addresses to Zoho CRM via ZOHO API. This is where we will accumulate what we call, "cold leads". 4) We need you to create a Wordpress page template for page checkouts, we already have the design and HTML. It simply needs turning into a template, then using Advanced Custom Fields plugin to set custom parameters for the page (Such as Zoho subscriptions product). We also need a the pricing calculator to work based on the product selected in this parameter, as well as the plan the user selected I can provide a detailed brief on request. We need excellent English skills as we would like to speak on Skype to detail the project before getting started