Firebase auth web invite to collaborate

Question

I am using Firebase Auth for web and Firebase Realtime database to create a simple application to share text notes. Users can sign up using email/password or Google/Facebook (federated identity management).

I am trying to understand if Firebase Auth has any good way of inviting users (web).

What I am trying to do is:

1. Logged in user1 creates a text Note
2. Logged in user1 shares the note with user2 that does not yet have an account
3. The system sends an invitation email to user2 for sign up
4. The invited user2 signs in and can read/edit the Note

I would ideally like for Firebase Auth to be able to

1. Create the account for user2 with a "sign up deadline" - for example 1 week - after that time the account will be deleted
   • I can then insert user id for user2 as editor for the Note
2. Activate the account when the invited user2 signs in for the first time.
3. Notify the application if/when the account is deleted due to no sign in
   • I can then remove the user id from the Note

Or maybe I am just over-complicating things - and there is a much more elegant way of handling this type of scenario? :)

I am using React/Redux and NodeJS/Express for front-/backend.