The McAfee Agent only communicates with ePO and the reposotories is that correct? Correct, you can view which systems the agent is connecting to by examining the SiteList.xml file. Also right clicking on the McAfee Agent icon and selecting About will show you the ePO Server/Agent Handlers that you are connecting to.
If there is a new virus signature file or product update it will update as necessary (if that is defined in the tasks). Correct you will need a Product Update Client Task that is configured to deploy the necessary files
However if there is no actual Anti Virus program installed it will not really do anything in terms of protection. Is this true? Correct, if VSE is not installed then nothing will be updated since no updateable products exist on the manage system.
The installation of either the McAfee Agent or the VirusScan client do not require reboots. I would recommend that you ensure that any necessary exclusions are in place in the VSE policies prior to server installations, as there are some performance issues that can arise.
This KB has lots of very useful information pertaining to exclusions.
Thank you very much for your help. I will take a look at the link and setup my policy exclusions before rolling out.