Would like to know if this fits my business needs

Hello, like the software and installed on my server, but just wondering if it will work for my business based on what I want to do before I start making all the changes…I already set up on server, I will be administrator, on my business intranet I will incorporate it via Iframe. I would like my agents to login to our back end and then thru there so it feels as part of our intranet, so far seems like they can as I have a test page.

Q. Do I register each of them as an employee? If so, how do they get the login and password registered?. Do they register here on your site and then login on our backended iframe?

Q. Will each employee have their own data base and independent CRM with their own clients, tasks and so on and will not see my own data?

Lastly: I’m adding business color scheme, will that show up for all of them or is each login and software linked separately with a different UI

Thank You