Save temporary registration data

You could save this as user_meta using [add_user_meta][1]. The options are usually used for sitewide settings, whereas the user_meta is specific for the single user.

add_user_meta( $user_id, $meta_key, $meta_value, $unique );

You can either delete the data on activation of the account, or leave it there – I do not see why you would want to delete it.

So the process should be

• create user
• add user meta
• send registration email
• your custom activation stuff

Everything okay so far?