hello
we just ran into the same issue or somewhat similar and found a slightly easier solution.
it turns out that you can create a user account into office 365 without any assigned license and this allows you to share documents/sites etc. with them through Sharepoint Online.
the steps we used:
go into Office 365 admin.
create user with name and last name + email address (the email address shouldn't be functional) and password.
go back to sharepoint and add the user to a group or share a specific document folder with them.
if they have access to the main site, then all they need is to go to the correct address: yoursite.sharepoint.com and login via office 365 with that email address.
et voila! ![Smile]()
