Casey,
Thank you for the recommendation of the Members plugin. I have been using it to debug this issue already.
When I test the exact set of capabilities that you supply in that screenshot it doesn’t solve my issue of not being able to create venues or organizers. I tried updating the permissions in the plugin and I tried using the Members plugin to create a new role with those permissions.
My problem is not with the ability for the user to create an event – that worked fine before. My problem is that the user can create an event but cannot create venues or organizers.