JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/handlebars.js/4.0.5/handlebars.min.js"></script>
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.1/css/bootstrap.min.css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.1/js/bootstrap.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.15/js/bootstrap-multiselect.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.15/css/bootstrap-multiselect.css">
<link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/gitana/alpaca@1.5.27/dist/alpaca/bootstrap/alpaca.min.css">
<script src="https://cdn.jsdelivr.net/gh/gitana/alpaca@1.5.27/dist/alpaca/bootstrap/alpaca.js"></script>
<div id="myForm">

</div>
<button id="disablefield">
  Toggle it!
</button>

JavaScript

$("#myForm").alpaca({
	"view": 'bootstrap-edit-horizontal',
  "schema": {
  	type: 'object',
    	properties: {
     		'thing': {
          "title": "Should be a select",
          "type": "string",
          "enum": ["foo", "bar", "bizz", "buzz", "boo"]
        },
        'thing2': {
          "title": "Should be a multiselect",
          "type": "array",
          "enum": ["foo", "bar", "bizz", "buzz", "boo"]
        }
     	}
  }
});
let disabled = false;
$('#disablefield').on('click', function() {
	const form = $("#myForm").alpaca()
  const thing1 = form.childrenByPropertyId.thing;
  const thing2 = form.childrenByPropertyId.thing2;
	if (disabled) {
		thing1.enable()
    thing2.enable()
  }
  else {
	  thing1.disable()
    thing2.disable()
  }
  disabled = !disabled;
})