Good evening David and welcome back!
Thank you for reaching out to us.
I would love to help you with this topic.
The simplest solution, by far, would be to use our Community Events plugin, which is geared precisely towards the level of control you are looking for: https://theeventscalendar.com/product/wordpress-community-events/
I do not believe there are specific capabilities that address these 2 options, unfortunately.
With that in mind, if you want to pursue with your present solution, you might want to read this: https://theeventscalendar.com/support/forums/topic/disable-editing-of-event-categories-for-editor-user-role-in-2016/
As for the import option, you could at least remove it for certain roles by adapting the following snippet: https://theeventscalendar.com/knowledgebase/disable-the-events-menu-on-the-dashboard/
Let me know if that helps.
Have a great day!
Geoff B.