You contradict yourself, when you say "differ essentially from one another by their respective data bus widths" and "8086 incorporates a 16-bit data bus and a 6

You contradict yourself, when you say "differ essentially from one another by their respective data bus widths" and "8086 incorporates a 16-bit data bus and a 6-byte instruction queue whereas the 8088 incorporates an 8-bit data bus and a 4-byte instruction queue.". In a sense 8088 has shorter pipeline. Shorter pipeline makes optimization techniques for 86 and 88 different, irrespective of the bus width - I mean, even if you slap 16 bit bus to 88, without changing the queue size, most efficient optimizations would still be different between these 2 CPUs.