Hello wildersites,
I can help you with your capabilities dilemma. The Events Calendar does have built in custom capabilities to create events.
So you can use the Members Plugin to create custom roles with the capabilities.
Members – Membership & User Role Editor Plugin
Once you create a role you can edit the capabilities and it will show the Events capabilities you can assign such as edit_tribe_events.
Then you can just check what you want the role to be able to access.
It can get a little tricky getting the settings correct, so usually I would make a clone of the role that does everything I want and then remove the capabilities I do not want.
Let me know if you have any questions once you get into it about the _tribe_events capabilities.
Thanks