It'll be possible to do from within the apps from the next release, at least on the Android app. Makes it a bit easier. We're also going to implement a feature where if someone doesn't already have an account, they'll be sent an email with a registration link that then gives them automatic access as soon as they've created an account.
Once notifications is available, notifications will be tied to the account, not the Almond+, so all users can have individual notifications.