Can i use EX8000 extender with Orbi system?

Netgear tech has stated that Nighthawk extenders in mesh mode will prefer connecting to the router if it is in broadcast range even if another stronger signal exists. At the moment Orbi is the only Netgear system that supports true peer-to-peer meshing. Nighthawk allows advanced user configurations as you are used to in standard routers and extenders. The Orbi system has a simpler setup and feature set aimed for home users. Orbi may or may not have the same range of coverage as the Nighthawk and you may still find deadspots  with just two satellites depending on how your house is set up and where you place the satellites.

The big question is whether Orbi will actually support a non-satellite extender. If it's possible to piggyback off the base, it may not exactly perform optimally. I would recommend either going with another Nighthawk extender to add to your current system or go completely with an entire Orbi setup. I am currently using a R8000P on the first floor which covers the ground floor decently and a EX8000 to strengthen the signal in the basement which has lots of deadspots from all the walls some devices have to go through and from all the large metal appliances.