Currently there is not a way to add multiple users or profiles to one account, though this may be an option in the future. Typically if a company would like to keep track of content uploaded by their customers, they would need to create separate accounts for each one.
Once you are set up with an account, you can generate as many tokens as you need.
Our API bearer token should never expire. There are special cases where a temporary one is generated, but all bearer tokens created via the page on the Developer console should be permanent.
Since the email will have the ability to change and recover the password to the account, the most typical setup would be to have a system email used where anyone who needs password access has access to that email.