Setting up to extract a project

I'm needing to extract on of our projects so a client can set up their own Jira system. I understand I need to set up a temporary instance of Jira to do this. Am I right in thinking I need to create all the user accounts, custom fields, workflows, permissions schemes etc in the temporary instance before importing the project. If so how can I get a list of all the users who have contributed to the project from the original project (which is in OnDemand). We have over 1200 issues in it and several hundred users who could potentially have contributed to it. Or will the user accounts be created automatically when the project is imported?