They will handle a lot more power than that too, BTW.

"1: Could the 16 NEO3´s be used with a crossover between 1-1,2KHz?"

That is not going to be a problem with 16 of them. I crossed them at 1.2kHz in the Epiphany 12/12 model (12 per speaker) and even lower in the 20/21 model that used 21 of them per speaker.

Just be sure that your crossover has them well down in output before they get too low. The Fs isn't much of a resonance, which helps a bunch, but it is in the 500Hz range, so keep that in mind.

"2: How is the sound of the non-PDR by less than +/- 30deg. horizontal off-axis compared to the PDR version? (Normally the PDR version is used)."

The off axis response is still not bad. It is an inch and a quarter wide playing surface so think of it just like a dome tweeter of that size.

The pdr version will give you better off axis response but will also give up about 3db in output. When they add the felt damping material to the sides they also drop out the two out rows of magnets.

I wanted it all too. So I had them build me a custom version that kept all five rows of magnets and used a denser felt in the sides but only on the front side (not the back side). This gave me the better off axis response of the pdr, smoother over all response, and the higher sensitivity of the standard version.

I had a large run of samples made so I could test them in a new design. I'll have 1000 units produced and have them in stock by mid summer. The cost will be the same as the standard units.

"3: the official price for the NEO’s is around 40$ each, does anyone know the price for roughly 40 units?"

If you need that many units then I'd contact a dealer for them (me) and ask for a good deal on them. I bet you'll be pleased.