Hi Jen,
I can answer your question, see my answer below.
I have no need for venue/organizer/costs, is it possible to disable these from showing up under add/edit event page(admin)?
There is no option in the plugin to disable these. You could do some customization to remove the menu links and on the edit page use css to hide those sections.
On the front end you could move the templates to your theme and remove those sections pretty easily following the themer’s guide.
https://theeventscalendar.com/support/documentation/events-calendar-themers-guide/
Does that answer your question?