JQuery Typeahead - AJAX Query DB and Update Fields

We require a simple integration of a jQuery Typeahead library (example referenced below) in an existing HTML/CSS and jQuery web application.

What should happen:
Case 1: if the user types a customer name (eg: Jane Doe), Typeahead will send and receive AJAX response, prompt the user to select the customer name, which will then auto-populate the other input fields. The user can also select "Create new customer..." from the Typeahead drop-down list and no fields will be auto populated.

Case 2: if the user types a customer name, and the AJAX response does not have the customer name, the user will select "Create new customer..." from the Typeahead drop-down list, and no fields will be auto populated.

Requirements:
HTML/CSS (Bootstrap 4)
jQuery > 3.5
and http://www.runningcoder.org/jquerytypeahead/overview/

Attached is copy of the PHP code which generates the AJAX response, excerpt of the HTML form itself. CSS framework is bootstrap.