Yes, obviously Purview - either an appliance or virtual server. See datasheet for virtual server requirements (
http://learn.extremenetworks.com/rs/extreme/images/Purview-DS.pdf). And yes, NetSight is required - the advanced version (part no. NMS-ADV-#). The advanced version is the only one with Purview capability. And yes, a K or S-series switch.
There are actually two bundled Purview solutions. They both include NMS-ADV-5 and a stand alone S-series switch (SSA-G8018-0652) 48-port 1Gbps SFP & 4x10Gbps SFP+, 2 power supplies, and up to 50,000 flows per minute Purview licensing. The PV-V50K-SYS supports a virtual Purview deployment. While the PV-50K-SYS comes with a dedicated Purview hardware appliance. If you need a copper based switch solution, you can build a solution with the SSA-T8028-0652 or some other S or K-series switch.
The Purview licensing is maintained centrally within NetSight and is distributed across multiple Purview engines (virtual or appliance) if there's more than one Purview engine.
You don't mention what wired or wireless vendor/components are installed. The NMS-ADV-5 is only licensed to manage 5 network (IP addresses) devices. If you'd like to manage more than 5 devices, simply go with a size to accommodate your requirements.
Lastly, NetSight can be deployed on virtual server, a dedicated appliance, Windows server, etc.
http://learn.extremenetworks.com/rs/extreme/images/NetSight-DS.pdf.
Hope this helps. Let us know if you have any more questions.
John