Passing theme suggestions to radio and checkbox children I have a simple radio button defined by with following YAML:

country:
  '#type': radios
  '#title': Country
  '#options':
    1: 'England &amp; Wales'
    2: 'Scotland'
  '#required': true
  '#theme_suggestion': minimal


The #theme_suggestion is my addition, in my .theme file I have the following code:

function HOOK_theme_suggestions_alter(array &amp;$suggestions, array $variables, $hook) {
  if (isset($variables['element']['#theme_suggestion'])) {
    $suggestions[] = $hook . '__' . $variables['element']['#theme_suggestion'];
  }
}


The combination of these options successfully allows me to override the twig templates for fieldset and radios e.g.:

&lt;!-- FILE NAME SUGGESTIONS:
   x fieldset--minimal.html.twig
   * fieldset.html.twig

   x radios--minimal.html.twig
   * radios.html.twig
--&gt;


However, these suggestions do not get passed down to the children (form_element, form_element_label and input__radio), I cannot find any documentation or examples on how to do this.
A possible way is to alter the form in which the radio is used if you know its id, or, for a broader solution, check for each form whether the radio is used.
Then you can call this function:

    function MY_CUSOMT_FUNCTION(&amp;$form, $theme_suggestion) {
     foreach (Element::children($form) as $child) {
     if (!isset($form[$child]['#theme_suggestion'])) {
       $form[$child]['#theme_suggestion'] = $theme_suggestion;
     }
     MY_CUSOMT_FUNCTION(&amp;$form, $theme_suggestion)
    }
   }


You can fine tune it to include only the children of your radio though