I'm currently writing some automated API tests and came across this thread.
Not sure if this is exactly what you are looking for, it might at least help someone else looking for similar information.
1) Get the event ids that you want to delete
If your events are public you can just use the API search endpoint:
GET /v3/events/search/
If some are drafts or not public, you cannot get them via API right now (I think, at least I have not seen anything in the documentation).
But you can get them from the ajax endpoints that the eventbrite website is using.
Just log in to the account that has the events and use these ajax endpoints
I'm sure you get the idea
2) Delete the events
You can just use the API to delete an event (the DELETE is currently not documented, but it works)
DELETE /v3/events/:id/
Hope that helps, might be easier to just delete the accounts and make new ones though :D