Assistant mode with limited access is a potential future feature of the app.
One solution for now
If the broker of the record or owner of the app needs his/her assistant to manage it, a simple solution would be for him/her to log in manually on the assistants phone without disclosing his/her password.
Once the assistant is logged in, she can manage the app.
The public facing email address can be configured in the admin console as well, if the broker of record only wants the enquires to be sent to another email address without giving admin access.