Good morning Brad and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the Eventbrite imports no longer working properly.
I would love to help you with this topic.
Do I need both plugins the events calendar and events calendar pro installed?
The simple answer is no. You do not need both plugins (unless you want their features).
What I believe is going on is that you are using a third-party plugin to do the import (Import Eventbrite Events Pro version 1.1.1 by Xylus Themes(http://xylusthemes.com)
Most properly, this plugin would need to be updated to work with the latest version of our plugins (4.4.5).
The alternative would be to downgrade our plugins: https://theeventscalendar.com/knowledgebase/downgrading-plugin-past-version/
Best regards,
Geoff B.