Is there a way to make sure people are receiving email updates from the site? I have directly messaged (to see if they are getting notifications in email) a few people without reply. Could something be off on the message getting to them in their inbox or should I reach out to make sure not simply going to Junk Mail?
You can send test emails from the Admin /admin/email to any address and see if they get through. You can also look at the logs at your mail processor, such as Mailchimp, etc. Finally, test your messages to see if they are likely to be caught by a spam filter with https://www.mail-tester.com/.