A nice summary, Bjørn.
I have just one little problem. The newest Capture NX-D will not display my D500 images. You can imagine what I think about that.
Between Photo Ninja and the older Capture NX2, I could find no real differences in conversion resolution, grain, etc. In all such pairings (old version or new versions) there will be distortion differences because I don't think PN carries lens distortion data.
If you wish to continue using NX2 for your D500 EF's, this guy might have the solution for you
http://www.bagnon.com/raw2nef/Works with Nikon Capture NX 2, version 2.4.6, and supports the following cameras: Sony A6000, Sony A7, Sony A7II, Sony A7R, Nikon D750, Nikon 7200, Nikon D810, Nikon D500 and Nikon D5.
I have none of these camera's but in the past downloaded D810 and D750 NEF's to play with. Worked like a charm with those files, with all the options of NX2 available.
I see no reason to expect it to behave different with a.o. D500 NEF's, nor have I so far read any feedback reporting otherwise,
It's free (although you can give a donation if you want) so little risk or investment required as far as that's concerned.