Hello, I understand you are having some issues with ‘tribe_get_organizer()’ and I can help you out with that.
I went in and edited the month/single-event.php that I moved to my theme and I as was able to see the Organizer when i did this:
<div id="tribe-events-event-<?php echo $event_id ?>" class="<?php tribe_events_event_classes() ?>" data-tribejson='<?php echo tribe_events_template_data( $post ); ?>'>
<h3 class="tribe-events-month-event-title entry-title summary">" class="url"><?php the_title() ?></h3>
<?php
$ID = get_the_ID();
echo tribe_get_organizer($ID);
?>
</div><!-- #tribe-events-event-# -->
Can you try to replace that coding in your custom template at the bottom and see if it shows up.
If nothing is showing could you try placing a word before the <h3> tag and see if that shows up.
Please let me know if that word does not show up and then can you provide the directory structure to where your custom templates are so we can rule that out as an issue.
Let me know what you find out and we can go from there.
Thanks