Hey @Steve,
These things are possible but are unfortunately not so without custom coding 🙁
We cannot help with custom coding but I have taken some to craft a free custom plugin for you to get you started on this – check out the code here: https://gist.github.com/ggwicz/cac1aa8265885b1440a3
If you add the code to your theme’s functions.php file, you should be able to achieve part 1 of your goals here; i.e., users who author events for review will get an email if their event has been approved and published 🙂
This works for me on my local testing site and I hope it works for you too!
I’m sorry that I don’t have the extra time to suss out your second request here; however, hopefully with the existing code I shared you can piece together similar code to achieve that. It should be rather simple, and you’d just need to use similar principles as the code I shared – but instead of dynamically generating the author email, you can just hard-code in the email address you’d like to be notified at 🙂 (you can use also use get_bloginfo( 'admin_email' )
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To learn more about the functions involved in doing this, check out these codex pages:
• https://codex.wordpress.org/Function_Reference/wp_mail
• https://codex.wordpress.org/Function_Reference/get_bloginfo
• https://codex.wordpress.org/Post_Status_Transitions
Cheers!
George