PBL, You are mistaken about the 8086 architecture. The 8086 is a true 16 bit architecture with full 16 bit data paths. it was the first member of the Intel family of processors to come out. I think you are thinking about the 8088, a chip that came out shortly after the 8086 as a lower cost alternative. The 8088 is the one with the 8 bit data path, and is incidently the chip around which the first IBM PC's were built.
The 80186 is a chip that has the identical core processor architecture as the 8086. The 80186 variant added many of the typical peripherals used in a system design to the processor chip. These included items like an interrupt controller, etc.
I was one of the four 8086 design engineers, and aided our Haifa facility in making the 8088 derivative. I also briefly was the leader of the 80186 design team during part of the product definition phase, and knew well the main design engineers who carried out the active design phase.
The intended difference of the 8088 from the 8086 was only in the external bus to memory, which had only eight data bits, unlike the 16 of the 8086. However, all internal data paths (which is what a microprocessor designer means by data path, though perhaps a pilot uses the words differently) were identical in the two chips. A few slight variations in microcode were required to work correctly with the external bus difference.
It is true that the 80186 CPU internals were strongly derivative of the 8086, but not that they were identical. For one example, the need for an 80188 variant was in the plan from the beginning, so was accommodated with a few wires and a few transistors, rather than the 10% relayout required to make an 8088 out of an 8086. For another example, Jim Klovstad took my suggestion to add an "execute next micro-op during jump" capability, which gave some performance improvement at extremely low cost. (I got the idea from a paper on on of the early MIT LISP machines). There were other differences on this order, though it is correct to say that the major departure in the machine was the integrated peripherals.
I'm not a pilot.