One night and a good sleep later (where I also got dizzy thinking about the universe...) I got the following solution:
To only load CKEditor for anonymous users if they click on answer or comment button you need to edit qa-page-question.php:
find line (around 240):
$qa_content['a_form']=qa_page_q_add_a_form($qa_content, 'anew', $usecaptcha, $questionid, @$anewin, @$anewerrors, $formtype=='a_add', $formrequested);
enclose it with this if statement:
if(isset($userid) || $formrequested) {
$qa_content['a_form']=qa_page_q_add_a_form($qa_content, 'anew', $usecaptcha, $questionid, @$anewin, @$anewerrors, $formtype=='a_add', $formrequested);
}
find line (around 258):
$qa_content['q_view']['c_form']=qa_page_q_add_c_form($qa_content, $questionid, $questionid, 'c'.$questionid,
$usecaptcha, @$cnewin[$questionid], @$cnewerrors[$questionid], $formtype=='c_add');
enclose it with this if statement:
if(isset($userid) || $formrequested) {
$qa_content['q_view']['c_form']=qa_page_q_add_c_form($qa_content, $questionid, $questionid, 'c'.$questionid,
$usecaptcha, @$cnewin[$questionid], @$cnewerrors[$questionid], $formtype=='c_add');
}
find line (around 360):
$a_view['c_form']=qa_page_q_add_c_form($qa_content, $questionid, $answerid, 'c'.$answerid,
$usecaptcha, @$cnewin[$answerid], @$cnewerrors[$answerid], $formtype=='c_add');
enclose it with this if statement:
if(isset($userid) || $formrequested) {
$a_view['c_form']=qa_page_q_add_c_form($qa_content, $questionid, $answerid, 'c'.$answerid,
$usecaptcha, @$cnewin[$answerid], @$cnewerrors[$answerid], $formtype=='c_add');
}
Done, seems to work.