Possibility of double opt-in (registration confirmation)?

That’s close to what the plugin’s default configuration is since the user needs to provide a valid email address to have their initial password sent to them (which they can change).

There is a post available to premium support subscribers that describes how to customize an activation process where an activation link is emailed to the user:
https://rocketgeek.com/filter-hooks/send-new-user-an-activation-link-in-the-new-registration-email/