Hey Sheila,
Thanks for reaching out to us!
There isn’t a different header file that you would edit for our event views. It will be the same header as everywhere else. Since the additional buttons aren’t showing in that particular area of the header, my first guess would be that they were added, possibly via the functions.php file, with a conditional that doesn’t include the events pages.
For example, if “is_page” was used, then it wouln’t show on the calendar views. For this, you could add the “tribe_is_event_query” conditional to ensure the additions show.
If this was added directly to a header.php file, with the customizations done by the former developer they could have created a new header within the theme “header-____.php” that would need to also be customized.
Let me know if this helps.
Thanks!