Here’s what we send reminders for:
Pending Users Reminder: if must approve users and pending_users_reminder_delay > 0 and there are new users who need to be approved older than the delay, then send a message to moderators.
Pending Queued Post Reminder: if notify about queued posts after > 0, contact_email is set, and there are posts that need to be approved (they aren’t publicly visible yet), then email the contact email.
So I’m guessing that this plugin doesn’t use the must approve users or approve post count settings. It will need to implement its own reminder.