How to set AUTHORIZATION on CREATE SCHEMA
You do not need to create a new user to be owner of the schema.

The default dbo owner is fine, especially if your adding the schema for organization reasons rather then security.

You do not need to create new users to access the new schema.

The only thing I would add is to make sure if you do change the owner from dbo, you change it to a domain service account or other permanent sql account. If the user gets deleted it can cause issues accessing the schema.