I don’t see why not – can you try adding a short snippet like this to your theme’s functions.php file?
add_filter( 'tribe_events_filter_values', 'reorder_category_filter_list', 10, 2 );
function reorder_category_filter_list( $list, $slug ) {
if ( 'eventcategory' !== $slug ) return $list;
usort( $list, 'custom_cat_filter_sort' );
return $list;
}
function custom_cat_filter_sort( $p, $q ) {
$slug_p = $p['data']['slug'];
$slug_q = $q['data']['slug'];
if ( $slug_p > $slug_q ) return 1;
if ( $slug_q > $slug_p ) return -1;
return 0;
}
Does that help?