So how did Dell get Kabylake for Q4 2016? I know this is only the U version, but the 13 MBP should be using the U version -- different story for the 15" version though.
You are correct. Dell is using a U-Version with Intel HD. Apple is waiting for a dual-core chipset that includes Iris graphics, which are a step up from Intel HD. The KL chipset appropriate for the 13" MBP should be available in Q1 2017 (ETA Feb).
The sad reality is that when the new form factor MBPs arrive, it is possible that Apple's flagship 15" MBP will be a generation behind in graphics performance compared to the 13" MBP because the former will likely be on Skylake while the latter will be on KL. The only way this could be mitigated is if the dGPU in Apple's 15" MBP includes the same ability as Intel's KL iGPU to process 4k video codecs. Still, the red-headed step child in this scenario would be the SL iGPU only 15" MBP which would presumably lack the necessary video codecs to allow the GPU to handle 4k.
My advice is to make sure that whatever you buy, you understand the capabilities of the GPU in the computer, be it integrated or discrete. Anyone caught with a Skylake computer with only Skylake integrated graphics is going to get left behind as companies (YouTube, Sony, Netflix, etc.) move to 4K content.