The current permission system is not always easy to grasp, and you can’t have a totally granular control over permissions... you can get good insight about how everything works reading
manager/actions/mutate_content.dynamic.php.
You’ll see that both item you need can only be accessed by the admin, from line 771 to line 808, let me just show the first lines :
<?php if($_SESSION['mgrRole']==1) { ?>
<tr style="height: 24px;">
<td><span class='warning'><?php echo $_lang['page_data_contentType']; ?></span></td>
(...)
?>
If you want to achieve what you need, I am afraid you’ll have to tweak the code, e.g check the ID for the Content Editor role in phpMyAdmin, in the modx_user_roles table.
Then if the role’s ID is say, 4, edit [tt]if($_SESSION[’mgrRole’]==1[/tt] and replace it with [tt]if($_SESSION[’mgrRole’]==1 || $_SESSION[’mgrRole’]==4 [/tt] in mutate_content.dynamic.php
Edit : I wondered why you needed editors to change content-type or content-disposition... it seems you don’t anymore, maybe it will help someone !