From the documentation on : https://world.mendix.com/display/howto40/Prerequisites
You have to define the Windows user that must be used to run the Mendix service and application. This must be a user without administrative rights. We recommend to restrict this user as much as possible and to give the user only rights to access the folders of the Mendix application.
So you need a user with access to the application folder and rights to start a windows service.
From your questions I understand that you have specific questions about IIS. Mendix allows you to deploy in windows without IIS. So IIS is not required to deploy Mendix on a windows environment.
If the url rewriter does n't support IIS 8.0 you can use the Application Request Routing
Thank you for the advice, but first i need to know which functionalities I minimally need to run a Mendix service.
This is a list of the functionalities that come with IIS 8.0 : http://technet.microsoft.com/en-us/library/hh831608.aspx
I also would like to know the minimum server role a mendix user needs?
Thanks in advance for your answers.