Question

How to show in tab "questions" only questions with answers ?

Answer 1

You can do this by adding a few lines immediately before the [ break; ] line that appears after [ case 'questions': ] in qa-page-home.php:

case 'questions':
  .. bunch of stuff you needn't change ...
  
foreach ($questions as $key => $question)
  if (!$question['acount'])
    unset($questions[$key]);

  break;