Hey Jesse,
Thanks for reaching out! To address things in reverse order, YES your event data will be fine when you add any of the premium products. To be clear, even when you buy a premium add-on you will not be deleting The Events Calendar. The Events Calendar is not a “free version”, it’s the “core” version of the calendar system. This is the backbone that all of the other add-on functionality is built upon.
However, even if you did The Events Calendar, the data would not be lost 😀
Now, as for Events Calendar Pro vs. Community Events, they do NOT have any features in common. Events Calendar Pro only provides the features listed for it on the Events Calendar Pro product page, and Community Events only provides the community-submission features.
You do not need one to buy the other; you can choose just the one that you most need and run it on your site alongside The Events Calendar.
I hope this information helps! Let me know if it does, or if there’s anything else I can try to help with.
Thanks,
George