BlueBomberTurbo

I do agree that DXO's rankings are a bit questionable, but not too far off.  There are generally valid explanations of the issues you cited:
NX500 over 5DS and NX1:  I've personally handled 5DSR files, and can say that the IQ is terrible. Even Canon stated not to expect much more than their old APS-C cameras in the IQ department.  I've read a few times that the NX500 is considered to have higher IQ than the NX1.  By how much, I don't know.  But viewing test RAWs of the NX1, I'd say DR and high ISO are around 1/2 stop behind the Nikon D7200.
  DXO One:  Its Super RAW literally is super.  It takes 4 RAW files, stacks them, and averages out the noise.  The difference is dramatic.  While the detail level isn't the best at high ISO, the lack of noise is well beyond FF capability.  This is similar to Olympus' high res RAW mode, but instead of increasing resolution, it reduces noise and increases detail at the same output size.
  D3X over D5:  The D5 is a bomb below ISO 1600, nearly matching the 5D III.  Even crop sensors beat it.  The sensor is tuned for mid/high ISO performance, though current technology only goes so far.  The gains, while there (+1/2 stop vs 1DX II), really aren't worth the trade off for the flexibility in low ISO RAW.  Worthy of note is that the D3X has a Sony sensor, while the D5 is Nikon's own creation.
  D600 over 1DX II and P40+:  It's true.  The D600 kills the 1DX II in DR at base ISO, and at worst, ties it the rest of the way up.  the 1DX II literally has years-old crop sensor performance in that area, despite Canon's massive gain in their new generation of sensors.  High ISO is also neck and neck.

Vs the P40+, the sensor in the MF camera is quite old.  Despite having the resolution advantage, it loses out in DR and high ISO by quite a big margin.  By ISO 1600, colors turn to mush, which doesn't really happen on the D600 at any ISO.
  D3s and D700:  I've also worked with files from a D700 multiple times, and can say that yes, its sensor is outdated at this point.  It's competitive with today's crop sensor cameras (minus Canon's) at best.  The A7S/II sensor has been compared to current medium format in its DR and ability to reproduce color. 

Once again, the D3s/D700's sensor is Nikon's own.  Nikon isn't very competitive when it comes to sensors, and probably had its best attempt at competing with Sony in the D4/s/f.  All of the rest of their sensors just don't stand out, though aren't as bad as Canon's. I have a feeling that resolution plays a big part in DXO's rankings.  If you downscale the A7R II's files to A7S II size, they will certainly have an advantage in their "Sports" rating. It might also be why the A7R II beats the D810, when the D810 clearly has about 1/3 stop advantage at high ISO.  My friend tested 2x A7R IIs before returning them and keeping his D810.  #IQsnob.
For DR and high ISO, they test noise up to a certain amount.  How they get to that amount, who knows, but it's a cutoff point they chose that represents the transition from "OK" noise to offensive noise.  So while sensors may have DR response up to a certain amount of stops, after a point, it becomes wiser to turn things back a bit in software.  Where that happens is up to the user, as it's a more subjective choice.
And "Color" is more about correctly reproducing color in RAW than how the final JPG is rendered.  Color in the Canon sense is highly subjective.  Color against a known testing scene/chart isn't.

Really? I'll have to test out the PPs in jpegs.
And what's this about preview in manual mode? Just last night I was playing with WB in manual mode and could clearly see a preview on the LCD screen if that's what you mean. I'm using an A6300.

Confused on the update. The A6300 (and presumably the A6500) does allow color depth adjustments when using an S-Gamut Color Mode. That's what the original EOSHD ProColor profile was. Am I missing something?

The email with updated settings is on its way today.
The update only applies to users of the A6300,A6500,A99 II and FS5. The update optimises saturation and colour depth on these cameras.
As the update is only for the cameras listed above, A7S II shooters for example do not need to change any settings.

That goes without saying for everything, always test new stuff before a shoot.
There are some bugs in Sony's colour handling. The different behaviour of colour depth from A7S II to A6300 shouldn't be happening.
I have made a second profile with a wider sweet spot, it delivers closer results across the different cameras, and you will all be getting it for free if you bought the original.
I am also working on something else completely new and an A6500 review.
I am now mega happy with Sony's colour after all this work.
I might sell my 1D X Mark II.

If it's only 20MP, how would it get 6K?  Especially with a 4:3 sensor.  The A6300 crops from 3:2 to 16:9 to get 6K from its 24MP sensor as it is...

Yup, prime, though I hear the AF speed is a bit slow compared to other native GH2 lenses. I'd say get that over the kit lens either way because of the significant difference in aperture. The kit lens is really only good in daylight unless you don't mind noise. Then just pick up a manual prime in a different focal length + adapter, and you have a good starter kit.

Yup, I've got one of those for my Nikon G (electronic aperture) lenses and it works just fine. Just be aware that if you're also using lenses with electronically actuated apertures, the adjustment ring on that adapter is very coarse, with a very short adjustment range (still goes from min to max aperture). It's pretty much impossible to get any type of repeatable precision when setting the aperture. If you're just adjusting aperture based on the appearance of the light and/or bokeh in the scene, that adapter is fine. But if you need to know the precise aperture setting being used, and/or be able to return to it later, you'll need an expensive adapter with a fine adjustment. One of the biggest reasons to get fully manual primes.

Canon and Nikon are pretty similar, though Nikons tend to be a bit sharper more often than not, especially when you get to the higher end primes that are also more contrasty and colorful. There are adapters for each specific brand/lens mount. Even the cheap ones work (around $25), though may need a bit of tightening (slip a knife in the prongs of the mount). If you look hard enough, you can probably get an old F/1.8-2.8 prime between 28-55mm without issues for as low as $50, though they usually hover around $100. Go wider/longer/faster and the price starts to go up.

The biggest limitation when using primes on a GH2 is when it comes to wide angles. You'll usually find down to 28mm cheaply enough, but things start to get more expensive past that. Primes tend to bottom out at 20mm, too, which is about a 40mm equivalent on the GH2. Not very wide. I have a Nikon-mount Tokina 11-16mm F/2.8 so I can go wider than that (about 22-32, wide enough), though it's above your suggested budget at $650 (and needs a slightly more expensive adapter because no aperture ring). Sigma makes a cheaper, slower, wide angle lens that can work, too. A bonus to these is that under good lighting, you can use ETC mode's additional 2.6x crop for a normal field of view. Like having two lenses in one! :)