[fandangos]

3. I'd say yes (I've just bought it and it's exactly what I needed), but it depends on what you want to do with it.
Do you only need a player for your Blu-Ray rips, which can play 4K HDR files while correctly passing through MaxCLL/MaxFALL metadata and passing through the audio track, be it Dolby Atmos or DTS:X, to your AVR? Then at the moment there's nothing better than the N2.
Do you also need any streaming service like Netflix or Amazon Prime video? Then get something else (or both the N2 and something else).

Is libbluray supported on N2? 
Also since it supports HDR pass trough do you know if it works for uhd blurays menus?

Also Odroid has a few different version C1, C2 etc. The N2 is the only one capable of HDR output?