Hi @dcantato,
I’m not exactly sure what page that screenshot represents but I don’t believe it’s one that is generated by our own plugin (though I realize it’s a representation of roles and capabilities).
In general, setting up community contributors as subscriber level users is more than sufficient. If you ensure that anonymous submissions are disabled this will mean you have a tier of users who can submit events but do little else.
If you wish, you could model a new user role on that of the existing default subscriber role (should you prefer not to use that role for any reason).
Does that help?