1. Technically what we have seen so far from chipworks are photographs of the SoC die most likely using a polarized microscope. This type of photographs give us the top-down view of the die photo (not xray)
http://images.anandtech.com/doci/7546/diecomparison.jpg . We have not truly seen the x-ray of both SoC unless you have seen ones that most of us haven't. A more appropriate picture would look something like TechInsights did for the Xbox One 8GB NAND, which is stacked. Unfortunately no one has the x-ray of the PS4 and XB1 SoC with similar resolution as below. Maybe you might get if you buy it for $2500 from TechInsights, which none of us can afford.
Xray of Xbox 8GB NAND
2. There is no evidence to show a physical dual GPU, so I am inclined to believe that such thing does not exist. We can see that from Chipworks die photo. Is it however possible that the one physical GPU functions similarly to the Intel HyperThread technology where one physical core can have two logical threads running concurrently? This goes back to MS claims that the XB1 GPU has "two independent graphics context" where one physical GPU can have two logical graphics contexts. The SDK is very lacking about this second graphics contexts so it's either this is used by the system only or that the SDK is still incomplete.
3. Quote "They certainly didn't wait to allow esram and DMA engines to be used. Why the slow down on dual tender pipes and GCPS and the dual GPU?" The SDK was a mess and many features such as "Descriptor Tables" have only been enabled since October 2014 SDK updates. Likewise, the feature Tiled Resources have only been finalized in the same October 2014 SDK updates. I am not saying the XB1 has dual GPU, but to answer this question may be rather simple from a software and tools perspective. The tools to use these "dual tender pipes..." are simply not ready. Without the eSRAM, the XB1 would be even more crippled due to limited DDR3 bandwidth, so they would have to prioritize the eSRAM and DMA over other features. And most likely, if these "dual" stuffs exist, they probably depend on eSRAM and DMA to work first. You can't run before you crawl and walk.