Support complex authentication/user management scenarios SSO

Dear all,
my goal is create an ecosystem of applications sharing a single authentication point and user profile provider based on Drupal 7.

I have created a "Drupal 7 Authentication Server" supporting the OAuth2 Standard using the OAuth2 LoginProvider and the OAuth 2 Server modules.

In this way I can get an acess token from external applications and access the user profile.
I have created an Angular JS client exploting the"Drupal 7 Authentication Server" to get an authentication token and access the user profile and I am going to create a "Drupal 7 Client" doing the same things.

As far as I understand the OAuth2 LoginProvider enables to read the user profile while it is not possible to write/modify it. Please correct me if I am wrong.

I still need to be able to:
1. Modify the user accounts from third parts applications: this would enable me to add a "modify user profile" page in my angularJS applications.
2. Create user accounts from third parts applications: this would enable me to create new user accounts from the .Net desktop application dedicated to system administrators (I know that they could create user accounts exploiting the Drupal GUI but they want this feature integrated in their existing application).

Thanks in advance for the support.
If you have similar issues I will be happy to share my experience with you.