How many system are unmanaged? I mean not communicating with your ePO server?
Have you deployed MA agent on them?
All system are on same network or Active directory?
Rogue System Detection (RSD) has nothing to do with any host being in Active Directory or not. An RSD sensor examines if a particular host is managed by the ePolicy Orchestrator server that the RSD sensor reports to. (Install an RSD sensor in each subnet so every subnet is covered (including subnets that hosts with permanent IP addresses are located) or install RSD sensor on DHCP server so all hosts querying IP address can be examined by the sensor.)
There are certain techniques that the RSD sensor uses to make this examination, but it only reports the managed status to ePO if a host is examined.
You need to create an ePO automatic response to deal with unmanaged hosts (this is the simplest way to get those hosts in management).
Or you can regularly create a list of unmanaged hosts by making a purpose-built ePO query, and you can use that list to install McAfee Agent to those hosts using a third party deployment tool.
2. You need to define a client task for updating in ePO. Then this task will be pulled by each managed host that sees this task. Please go to My Organization level, select Assign Client Task and select New Task. This can be the default update task for hosts created in the uppermost level.
3. I did not quite understand what you mean by this question. Could you tell it using different words?