Not sure what you're hoping to accomplish, ultimately, with all this moving of data. If it was me in a similar situation, based on what I know thus far, I'd focus more on limiting what event posts get queried for. For instance, if you need a specific url on the site to show only 2016 events, use pre_get_posts or so to limit to just 2016 events. You could even keep it dynamic using PHP's date() function to get the current year, so you don't have to manually update next year.
A lot cleaner idea than trying to migrate posts between post types all the time, at least in my mind.
