Do I need to create different logins to access Host/Organization/Attendee profiles

No, you only need one user for access to all of these portals.

You only need one user for access to all of these portals. You can manage an event as a Host, join as an Organization (exhibitor), or view as an Attendee (jobseeker) by clicking the blue To Lobby button in your manage event screen (all with the same user).

However, you may not register for an event you are Hosting as an Attendee. Your Host portal will allow you to view the event as an Attendee by the Lobby button in your Event Details page.