Unfortunately No, you must select Parent Content Type
for each new site content type.
Regarding hiding Recurrence
and All Day Event
columns, you alright theses fields is not clickable in event content type setting to change its site columns setting to Hidden (Will not appear in forms)
.
Meanwhile, to achieve your goal to hide Recurrence and All Day Event fields you can use jquery in script editor in your new and edit page as the following:
- Open your new item page in new tab.
- Edit the page > add script editor.
- Add the following code
Code
<script src="https://code.jquery.com/jquery-1.11.0.min.js"></script>
<script type="text/javascript">
$(document).ready(function()
{
$('nobr:contains("All Day Event")').closest('tr').hide();
$('nobr:contains("Recurrence")').closest('tr').hide();
});
</script>