User activation email not being sent

Hi again-

We noticed the user isn't getting the activation email upon subscribing to a plan. We did a mass data load of around 3500 names, so we turned off site notifications, but thought that would have just been for PayPlans, and not the user activation email (since that's core Joomla)

So two questions...

1) If we turn this back on, will this send out notifications to users that were already added, or only new users after it's switched on? I didn't know if there was an email spool or something that would send once turned back on. It would be a nightmare scenario if the users already added would be sent an account activation email.

2) If the answer to #1 is "no emails will be sent to existing users, and only new users", can you please let me know how to turn this back on, or see if there's another reason why the user activation email isn't being sent? There was a developer who worked on this project, but that was several months ago, and he's not available any longer.

Btw, if you need creds, they're in the ticket at https://stackideas.com/forums/2co-after-purchase

Thanks again!
Kevin