City and street validation at checkout

I am a newcomer in Magento2 and face with a next task. I have to do custom validation for city and street inputs at Checkout page for both shipping and payment steps.
There are 2 issues I am misunderstanding totally.

1. As I could investigate templates for city and street are inserted by Knockout. To get cities and streets list I have to insert php method in script tag. This php method provides to me URL for next Ajax request. Because of general Knockout template with ‘.html’ type I can’t insert php code there.
   So how can I call my js file from Knockout html template?
2. City and street inputs must offer coincidences for first entered letters (as a result of Ajax request) in their lists below. How this lists can be realized?

I have read Magento devdocs and a lot of communities but couldn’t find intelligible explanation. Sorry for possible repeat.

app/design/frontend/Vendor/Theme/Magento_Checkout/web/template/shipping-address/form.html (inputs are inserted inside id="shipping-new-address-form")

<div class="amtheme-shipping-wrap">
    <form class="form form-shipping-address amtheme-form-address"
          id="co-shipping-form"
          data-bind="attr: {'data-hasrequired': $t('* Required Fields')}">
        <div class="step-title" data-bind="text: setAddressTitle" data-role="title"></div>
        <!-- ko foreach: getRegion('before-fields') -->
            <!-- ko template: getTemplate() --><!-- /ko -->
        <!--/ko-->
        <div id="shipping-new-address-form" class="fieldset address">
            <!-- ko foreach: getRegion('additional-fieldsets') -->
                <!-- ko template: getTemplate() --><!-- /ko -->
            <!--/ko-->
            <!-- ko if: (isCustomerLoggedIn) -->
            <div class="field choice" data-bind="visible: !isFormInline">
                <input type="checkbox" class="checkbox" id="shipping-save-in-address-book" data-bind="checked: saveInAddressBook" />
                <label class="label" for="shipping-save-in-address-book">
                    <span data-bind="i18n: 'Save in address book'"></span>
                </label>
            </div>
            <!-- /ko -->
            <div class="amtheme-address-toolbar" data-bind="visible: !isFormInline && !isFormPopUpVisible()">
                <button type="button"
                        class="action action-cancel"
                        click="hideNewAddress"
                        text="$t('Cancel')"
                        data-bind="attr: {title: $t('Cancel')}">
                </button>
                <button type="button"
                        class="action action-save"
                        click="saveNewAddress"
                        text="$t('Ship here')"
                        data-bind="attr: {title: $t('Ship here')}">
                </button>
            </div>
        </div>
    </form>
</div>

I was about to write inside form.html something like this:

<script>
    require([
        'jquery',
        'Magento_Theme/js/govaddress-validation'
    ], function($) {
        $(function () {
            $('input[name="city"]').keyup(function () {
                console.log('keyup event worked');
                govAddressValidation.getCityList('<?php echo $this->getUrl("opgovaddress"); ?>');
            });
        })
    })
</script>

My JS file is not matter as it is unreachable for now

app/design/frontend/Vendor/Theme/Magento_Theme/web/js/govaddress-validation.js

define([
    'jquery'
], function ($) {
    'use strict';
    return {
        url: '',
        getCityList: function (url) {
            var inputValue = $('input[name="city"]').val();
            this.inputValue = inputValue;
            this.url = url;
            this.ajaxCall();
            console.log('getCityList');
        },

        ...
    }
})

app/design/frontend/Vendor/Theme/Magento_Theme/requirejs-config.js

var config = {
    map: {
        '*': {
            backTop: 'Magento_Theme/js/components/back-to-top',
            amMenu: 'Magento_Theme/js/components/am-menu',
            amQty: 'Magento_Theme/js/components/am-qty',
            amSelect: 'Magento_Theme/js/components/am-select',
            amFileUpload: 'Magento_Theme/js/components/am-file-upload',
            amStickyHeader: 'Magento_Theme/js/components/am-sticky-header',
            govAddressValidation: 'Magento_Theme/js/govaddress-validation'
        }
    },

    config: {
        mixins: {
            'mage/validation': {
                'Magento_Theme/js/lib/mage/validation-mixin': false
            },
            'mage/menu': {
                'Magento_Theme/js/lib/mage/menu-mixin': true
            }
        }
    }
};