Great glad it helps. See my answers below:
Cool, that helps. Another question: can I create a custom class file in that folder without it being erased during an upgrade?
I am afraid not. WordPress deletes the entire plugin’s directory when updating. It is best to put the coding in a custom plugin.
Also, where is the Ajax code for the Previous Week/Next Week actions in the Week view?
The AJAX is controlled by this file:
\events-calendar-pro\resources\tribe-events-week.js
That is the scripts, but the plugin uses the minified version
\events-calendar-pro\resources\tribe-events-week.min.js
Look for this function around line 407:
$tribe_container
.on( 'click', '.tribe-events-nav-previous, .tribe-events-nav-next', function( e ) { ... }