I agree with most of your comments but if you look at the first photo there is a definite DSLR-style slope to the area around the shutter release, a slope that is clearly absent in the latest shot and I don't think that can be accounted for but the angle of viewing. And the 'prism housing' looks like a different shape.
That's a parallax sort of sitch to me. The latest shot is simply at a lower angle so it's hard to see other features we could see in the earlier ads. That's why you can't see the diopter / eye adjustment knob, the hotshoe, etc.
Also, the latest shot has clearly been massaged in PS and/or was covered up in use to not have a leak or social media reveal. It honestly looks like a gradient fill paint bucket was applied on the 'pentaprism' area.
So I think there's a chance
these three shots over time during this campaign are describing the same form factor body:
I also think the three different diameter lenses above are confounding how the mount to 'pentaprism' transition looks, and (call me crazy) that might be deliberate to eff with us. The left shot is a smaller diameter (perhaps a 67?) 24-something slower/longer zoom. The middle could be the 50-ish f/0.95 we've heard about as the barrel would appear to to be sized as big as the mount transition to the pentaprism, which would be enormous. And the third one looks like a 100 macro (or maybe a svelte 35 f1.4) to me. And there are clearly two different sizes of hands here.
I think Nikon is screwing with us here to prevent any clear connecting of dots from happening until launch. I applaud these little cloak and dagger moves -- this is fun for me.