I am not sure I would recommend it!

But you could use one of the Powerlink outputs of the Sound Center - with the appropriate adapter cable.

And connect that cable to the (analog) input port of the Naim.

You would have to configure the PL out as ‘line-out’ or ‘other’ and choose the role that your Piegas would have (Fronts or surrounds?) with the Eclipse.

The Naim is a 2 channel device aka stereo.

Then you would have to choose that input on the Naim and volume regulate it according to the general volume choosen for the Eclipse…..which will be a PIA in daily use, I guess.

You could use the eARC to connect the ATV directly, but then there will be no sound from the Sound Center and (probably) no control of the ATV through the BV/Beoremote.

MM

Without a control system to manage the volume this would probably be a pain in the neck. 

What you're essentially looking for is a 3.0 or 3.1 setup - such that the TV would be your dialog/center and the Piegas would be your front left and right channels. You'd need to switch on the Uniti Nova and match the relative volumes. 

I can and have made things like this work with systems like Control4 because you can activate the products, inputs, and set relative volumes easily - otherwise you'd be doing a lot of fussing every time you want to watch TV. 

I have a Uniti Atom and I'm absolutely in love with it so I understand the desire to involve it, but I wouldn't say it's simple.